Segmentation fault with QtCreator on Ubuntu 12.04 Beta

I just updated to Ubuntiu 12.04 Beta
When i run QtCreator it gives me 1 to 4 times a Segmentation fault and it makes a core dump
before it starts finaly up

When Qt then started it gives me the two followings error lines in the terminal
libpng warning: Interlace handling should be turned on when using png_read_image
libpng warning: Interlace handling should be turned on when using png_read_image

don't know if the last errors have to do with the first dump !