malloc error on show() oder x/ylabel()

i’m running python 2.7, matplotlib-1.0.1, gcc 4.2.1 and grortran 4.2.1… when invoking (successful importing import matplotlib.pyplot as plt) in combination with plt.xlabel or savefig(“”) give me that nasty malloc error:

Python(19725,0x7fff7055fca0) malloc: *** error for object 0x102d8c6c0: pointer being freed was not allocated

*** set a breakpoint in malloc_error_break to debug

Abort trap

calling or x/ylabel(“string…”) alone doesn’t get me that error…