VB6 program fails opening Excel 2007 with Automation Error Library not registered - vb6

Question

I created this VB6 program on my Windows 7 32bit machine with Office 2010 32bit, which runs fine. Tested it on a Windows 8 64 bit machine with Office 2013 32bit, it works. On one machine with, Windows 7 64 bit and Office 2007(32 bit only) it throws an error during the following piece of code.
The actual error message:
Run-time Error –2147319779 (8002801d) Automation error, Library not
registered
VB6 Code:
If (excel_app Is Nothing) Then
Set excel_app = CreateObject("Excel.Application")
Else
Set excel_app = GetObject(, "Excel.Application")
End If
excel_app.Visible = True
excel_version = excel_app.Application.Version
Set wBook = excel_app.Workbooks.Open(directory_path & "\templates\book1.xlsm")
So it is throwing the error when I open book1. It actual does open it and it has a macro run on Workbook_Open(), this runs right through seemly fine. After it finishes and processing of the program returns to the VB6 program it throws the error.
Here are the project references:
Has anyone come across this and what would be the fix?
[EDIT]
I am obviously doing something wrong here my error handler is throwing an error.
I did try one other thing and that was removed "Set wBook = " and it didn't throw an error. I have placed "Set wBook = " back since then, as I do need it further on in my code.
Dim wBook As Workbook
Dim excel_app As Object
On Error GoTo trialhandler
If (excel_app Is Nothing) Then
Set excel_app = CreateObject("Excel.Application")
Else
Set excel_app = GetObject(, "Excel.Application")
End If
excel_app.Visible = True
excel_version = excel_app.Application.Version
Set wBook = excel_app.Workbooks.Open(directory_path & "\templates\book1.xlsm")
MsgBox ("Exiting")
Exit Sub
trialhandler:
Dim source_string As String
source_string = excel_app.Source 'Error here
MsgBox ("My Error 1:" & source_string)
excel_app.Err
MsgBox ("My Error 2:" & excel_app.Err.Number & " " & excel_app.Err.Description)
Exit Sub
I had Office 2013 installed on this previously, then uninstalled it and placed 2007 on it, could this have any impact? Or the fact that I have created this program with reference to Excel 2010 and now I'm trying to run it against Office 2007? Though it works on the other machine with 2013. Grasping at straws here.
[EDIT 2]
It has passed the initial error to throw exactly the same error later on. This piece imports an mdb table. There must be some early binding left over
With wBook.Worksheets("Seal Register").ListObjects.Add(SourceType:=0, Source:=Array( _
"OLEDB;Provider=Microsoft.ACE.OLEDB.12.0;Password="""";User ID=Admin;Data Source=" & db_full_path & ";" _
, _
"Mode=ReadWrite;Extended Properties="""";Jet OLEDB:System database="""";Jet OLEDB:Registry Path="""";" _
, _
"Jet OLEDB:Database Password="""";Jet OLEDB:Engine Type=5;Jet OLEDB:Database Locking Mode=0;Jet OLEDB:Global Partial Bulk Ops=2;" _
, _
"Jet OLEDB:Global Bulk Transactions=1;Jet OLEDB:New Database Password="""";Jet OLEDB:Create System Database=False;" _
, _
"Jet OLEDB:Encrypt Database=False;Jet OLEDB:Don't Copy Locale on Compact=False;Jet OLEDB:Compact Without Replica Repair=False;" _
, _
"Jet OLEDB:SFP=False;Jet OLEDB:Support Complex Data=False"), _
Destination:=Range("A" & row_number)).QueryTable
.MaintainConnection = False
.CommandType = xlCmdTable
.CommandText = Array(db_table_name)
.RowNumbers = False
.FillAdjacentFormulas = False
.PreserveFormatting = True
.RefreshOnFileOpen = False
.BackgroundQuery = True
.RefreshStyle = 1
.SavePassword = False
.SaveData = True
.AdjustColumnWidth = True
.RefreshPeriod = 0
.PreserveColumnInfo = True
.SourceDataFile = db_full_path
.ListObject.DisplayName = "Table_" & db_table_name
.Refresh BackgroundQuery:=False
End With

Answer 1

There no reason to think this is a vb error.
Returns or sets the name of the object or application that originally generated the error.
object.Source [= stringexpression]
Arguments
object
Always the Err object.
stringexpression
A string expression representing the application that generated the error.
Remarks
The Source property specifies a string expression that is usually the class name or programmatic ID of the object that caused the error. Use Source to provide your users with information when your code is unable to handle an error generated in an accessed object. For example, if you access Microsoft Excel and it generates a Division by zero error, Microsoft Excel sets Err.Number to its error code for that error and sets Source to Excel.Application. Note that if the error is generated in another object called by Microsoft Excel, Excel intercepts the error and sets Err.Number to its own code for Division by zero. However, it leaves the other Err object (including Source) as set by the object that generated the error.
Source always contains the name of the object that originally generated the error — your code can try to handle the error according to the error documentation of the object you accessed. If your error handler fails, you can use the Err object information to describe the error to your user, using Source and the other Err to inform the user which object originally caused the error, its description of the error, and so forth.
From Automating Microsoft Office 97 and Microsoft Office 2000
Lori Turner
Microsoft Corporation
March 2000
PROBLEM:
My Automation client worked fine with the Office 97 version of my application. However, I rebuilt my project and it works fine with Office 2000 but now fails with Office 97. What could be wrong?
New versions of Office include new features and enhance some of the existing ones. To provide clients with programmatic access to these new and enhanced features, the object models must be updated. Because of this update, a method may have more arguments for Office 2000 than it did with Office 97.
The new arguments to existing methods are usually optional. If you use late binding to the Office Automation server, your code should work successfully with either Office 97 or Office 2000. However, if you use early binding, the differences between the 97 and 2000 type libraries could cause you problems in the following situations:
If you create an Automation client in Visual Basic and reference the Office 2000 type library, your code might fail when using an Office 97 server if you call a method or property that has changed.
If you create an MFC Automation client and use the ClassWizard to wrap classes from the Office 2000 type library, your code might fail when using an Office 97 server if you call a method or property that has changed.
To avoid this problem, you should develop your Automation client against the lowest version of the Office server you intend to support. For the best results in maintaining compatibility with multiple versions of Office, you should use late binding. However, if you choose to use early binding, bind to the type library for the earliest version of the Office server you want to support. To illustrate, if you are writing an Automation client with Visual Basic and want that client to work with Excel 97 and Excel 2000, you should reference the Excel 97 type library in your Visual Basic project. Likewise, if you are writing an Automation client using MFC, you should use the ClassWizard to wrap the Excel 97 type library.
For more information, please see the following article in the Microsoft Knowledge Base:
Q224925 INFO: Type Libraries for Office 2000 Have Changed