Launch process under another user account - vb6

Question

Below is the sequence of Process calling;
Service calling Process A (this causes Process A to run under local system account).
Process A launching Process B under different user account (non admin user) using CreateProcessWithLogonW API (as logon credentials of different user is available).
Process B performing some activity which involves invoking another process.
Up to step 2 everything works fine. Process B launched under given user account but Process B is not able to perform a task like executing batch file or launching one more process using CreateProcess API.
Below is the code for invoking Process B;
Dim si As STARTUPINFO
Dim pi As PROCESS_INFORMATION
Dim wUser As String
Dim wDomain As String
Dim wPassword As String
Dim wCommandLine As String
Dim wCurrentDir As String
Dim wApplicaiotnName
Dim Result As Long
si.cb = Len(si)
si.lpDesktop = "WinSta0\Default"
Result = CreateProcessWithLogonW(wUser, wDomain, wPassword, _LOGON_WITH_PROFILE,
wApplicaiotnName, "", _CREATE_UNICODE_ENVIRONMENT, 0&, wCurrentDir, si, pi)
And below code used in Process B to execute batch file;
Dim proc As PROCESS_INFORMATION
Dim start As STARTUPINFO
Dim ret As Long
Dim lpId As Long
Dim llReturn As Long
Dim RetVal As Long
With start
.cb = Len(start)
.lpDesktop = "WinSta0\Default"
If Not IsMissing(WindowStyle) Then
.dwFlags = STARTF_USESHOWWINDOW
.wShowWindow = WindowStyle
End If
End With
ret& = CreateProcessA(0&, pathName, 0&, 0&, 1&, _
NORMAL_PRIORITY_CLASS, 0&, 0&, start, proc)