I think your problem is due to you asking perl to only read a content length of 1024. It's reading up to 1024 and then it stops. Change 1024 to $ENV{'CONTENT_LENGTH'} and see if it helps. But i keep getting negative XP for talking about file uploads. My limited but travailed experience has led me to understand the read statement as follows.

read(HANDLE, STUFF, LENGTHOFSTUFF);
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