hmmm you're right, but i think i know now why you get these messages.
Did you set warn_level to 3 ?
In the manual under warn_level :
0 - no warning messages.
1 - warnings about problems with some hardware configurations (default).
2 - warnings about bad texture sizes and wrong parameters in engine functions.
3 - warnings about missing files in file functions.
4..6 - even more warnings.

so you probably have warn_level at 3 or higher and everything works as planned ^^