No problem. Here is the actual HTML used in the page (I had to pull the other from memory since the website seems to be down ;), and the Perl code:

<FORM METHOD=POST ACTION="http://www.environet.gov.on.ca/dwws-app/DWWS
+App?cmd=UploadSubmPage.uploadSubm" ENCTYPE="multipart/form-data">

<input type="hidden" name="works_id" value="3253245">
<input type="hidden" name="lab_id" value="2435325">
<input type="file" name="filename">

</FORM>
[download]

And the Perl code responsible:

$FileName = ("C:\\Scripts\\moe\\swap\\$LotNumber.txt");

my $request = POST ('http://www.environet.gov.on.ca/dwws-app/DWWSApp?c
+md=UploadSubmPage.uploadSubm',
Content_Type=> 'form-data',
Content => [works_id=>'2353245',
lab_id=>'456436',
filename=>[$FileName]]);
[download]

The '?' character being escaped sounds like it may be significant. Anyways, hope this helps...

-Tim