powershell not seeing filesystem change - "cannot find path" - windows

Question

I wrote a powershell script that exports a bunch of files from a Dynamics NAV instance. It calls a perl script that I also wrote that then splits all of the files into individual objects and sticks them in subdirectories under a dir I create in perl. Then the powershell script attempts to copy the files to a different dir, and fails.
Powershell generates the dir name:
$datestamp = get-date -f MM-dd-yyyy_HH_mm_ss
$dumpdir = "\temp\nav_export\" + $env:username + "\" + $servicetier + "~" + $database + "~" + $datestamp;
Then powershell does a bunch of stuff that works fine, and calls the perl script ($servicetier and $database are defined earlier in the script):
& c:\navgit\split-objects.pl $servicetier $database $datestamp
perl proceeds to create the directory and split the files correctly:
use strict;
use warnings;
use File::Path qw(make_path remove_tree);
my $username = getlogin || getpwuid($<);
my $servicetier = $ARGV[0];
my $database = $ARGV[1];
my $datestamp = $ARGV[2];
undef #ARGV;
my $work_dir = "/temp/nav_export";
my $objects_dir = "$work_dir/$username/objects";
my $export_dir = "$work_dir/$username/$servicetier~$database~$datestamp";
print "Objects from $servicetier~$database being exported to $export_dir\n";
make_path("$export_dir/Page", "$export_dir/Codeunit", "$export_dir/MenuSuite", "$export_dir/Query", "$export_dir/Report", "$export_dir/Table", "$export_dir/XMLport");
chdir $objects_dir or die "Could not change to $objects_dir: $!";
<does all of the filehandling and parsing>
Control returns to the powershell script, which tries to finish with:
Copy-Item -Path $dumpdir -Destination $cwd -Force -Recurse
But that throws the error:
Copy-Item : Cannot find path 'C:\temp\nav_export\danielj\cen-dev-erp-st1~JustFoodERP-PROTO~01-20-2015_19_26_50' because it does not exist.
At C:\navgit\nav-export.ps1:175 char:1
+ Copy-Item -Path $dumpdir -Destination $cwd -Force -Recurse
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : ObjectNotFound: (C:\temp\nav_exp...0-2015_19_26_50:String) [Copy-Item], ItemNotFoundException
+ FullyQualifiedErrorId : PathNotFound,Microsoft.PowerShell.Commands.CopyItemCommand
The directory I'm trying to copy from does exist. But powershell doesn't see it! I added some code to list the contents of the parent dir:
Copy-Item -Path $dumpdir -Destination $cwd -Force -Recurse
Write-Host "Copy-Item -Path $dumpdir -Destination $cwd -Force -Recurse"
$test = "C:\temp\nav_export\$env:username"
Get-ChildItem $test -Force
Copy-Item -Path \temp\nav_export\danielj\cen-dev-erp-st1~JustFoodERP-PROTO~01-20-2015_19_26_50 -Destination C:\Users\danielj\erp\ -Force -Recurse
Directory: C:\temp\nav_export\danielj
Mode LastWriteTime Length Name
---- ------------- ------ ----
d---- 1/20/2015 6:32 PM cen-dev-erp-st1~JustFoodERP-PROTO~01-20-2015_18_32_33
d---- 1/20/2015 7:08 PM cen-dev-erp-st1~JustFoodERP-PROTO~01-20-2015_19_08_49
d---- 1/19/2015 1:07 PM cen-dev-erp-st1~JustFoodERP-PROTO~20150119-130747
d---- 1/20/2015 7:26 PM logs
d---- 1/20/2015 7:26 PM objects
-a--- 1/20/2015 7:26 PM 309 objects.bat
-a--- 1/20/2015 1:41 PM 436 soap_envelope.txt
If I do a directory listing from outside the script, there it is:
PS C:\Users\danielj\erp> $test = "C:\temp\nav_export\$env:username"
Get-ChildItem $test -Force
Directory: C:\temp\nav_export\danielj
Mode LastWriteTime Length Name
---- ------------- ------ ----
d---- 1/20/2015 6:32 PM cen-dev-erp-st1~JustFoodERP-PROTO~01-20-2015_18_32_33
d---- 1/20/2015 7:08 PM cen-dev-erp-st1~JustFoodERP-PROTO~01-20-2015_19_08_49
d---- 1/20/2015 7:26 PM cen-dev-erp-st1~JustFoodERP-PROTO~01-20-2015_19_26_50
d---- 1/19/2015 1:07 PM cen-dev-erp-st1~JustFoodERP-PROTO~20150119-130747
d---- 1/20/2015 7:26 PM logs
d---- 1/20/2015 7:26 PM objects
-a--- 1/20/2015 7:26 PM 309 objects.bat
-a--- 1/20/2015 1:41 PM 436 soap_envelope.txt
I've tried calling an external script from the main powershell script after perl is finished, and the results are the same.
Why would powershell not see the directory or files that were created by the perl script? And more importantly, how can I get it to do so?

Answer 1

Are you sure that everything proced in the exact order you assume it does ?
try to start your perl script like this :
& c:\navgit\split-objects.pl $servicetier $database $datestamp | Out-Null
It makes sure that your Perl part is terminated when the PowerShell execute the rest of your script.

Answer 2

I ended up just creating the directory in powershell in the first place. No reason it should have to have been created in the perl script.
It'd still be nice to know why it didn't work the way I'd have expected though.