Sometimes the name of the currently edited file is inserted somewhere in the source code.
I cannot detect a pattern or anything, but when I get parse errors in PHP this sometimes is due to a filename in the source that I definitely did not put there myself

This behaviour already occured in Webuilder 2006 (V7.4 I think) and still exists in 2007 (V8.0.0.75). I am on WinXP SP2.