As a programmer, one is not surprised if a compiler says "semicolon expected" or "semicolon missing".
But I just had the case where I got the following error message for an XSLT I'm working on:
Error in package file transformation: Could not load package stylesheet file: Semicolon expected
Semicolon? XML? Wait! What...?
The culprit was an "HTML Entity"
If you ever get the error "semicolon expected", first look at all HTML entities you're using - and make sure they are properly terminated with a ";".
Took me 15 minutes to find this - and I'm somewhere between amused and embarrassed