So i took the opportunity to rewrite the whole thing and do pretty much everything with Perl, not using external commands like "unzip" and "wget". This should make things a bit more portable.

Very good (++). I must say that this was one of the first things which struck me while reading your original post and thought that it would be a good exercise to bring everything into Perl instead. Now having both posts here is a nice example for how to do just that.