There might be some regexp-type characters in your $PartNumber variable. To make sure they don't screw anything up, you might want to do this: 
if ($main::fields[0] =~ /\Q$PartNumber\E/)
{
     # ...
}

[download]
The case might be that $PartNumber contains, for example, brackets.

Also, where does $PartNumber originate? It looks like a global, though if you're not using strict you never really know.

Although it's not strictly important to the way your program operates, I'd suggest that using brackets when calling functions is preferable to ampersands. For example:
continue();
Perl 4 required ampersands, so they're left in there for compatibility reasons, mostly, but are otherwise deprecated.

Update:
Based on your earlier post I think that you might be able to do a straight eq comparison instead of a regular expression match, provided you're typing in the literal part number, character for character. 
if ($main::fields[0] eq $PartNumber)
{
     # ...
}

[download]

In reply to Re: Missing the if statement and going directly to else by tadman
in thread Missing the if statement and going directly to else by Bismark

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