I dare not use strict or warnings, because there appears to be a lot going on behind the scenes and I have no clue how it may affect things.
warnings and strict are very useful for precisely this situation; they will let you know if weird shit is happening behind the scenes. There also exists use diagnostics; for even more verbosity. I strongly recommend you enable warnings and strict checking, and see if something pops out at you.
In general, if warnings and/or strict break things, things were already broken to begin with.