i had a very large tileset, reducing it was the solution. i had also a sprite sheet of 28x42, this isn't power of two, right? there was no error because of it.
my friend asked me yesterday, why his graphics card could play 3d games, but not show this large texture. he said the IDE must be not so good. the texture was 912x397, and i made a sheet with 1 row and 3 columns out of it ( 3x912 ).
the graphics card is an Intel 82845G/GL/GE/PE/GV Graphics Controller, 64MB memory. i said modern 3d games don't use so big textures like i did, but what do you say?