@Ottawa:
My *.lvl files contains characters..

@Lukas:
Yes, I'm the one making my *.lvl files and just access it through file_open_read.. Actually that's what I think also that files starting with number are not possible in a resource file, then I've tried yesterday before your replies by just renaming 1.lvl to sample.lvl but still the same result.

@Tobias
I'll try that approach..

Thanks all!!!