设置交叉编译环境时，bitbake后出错

运行bitbake fsl-image-core后，报出警告，如下：
NOTE: Preparing runqueue
NOTE: Executing SetScene Tasks
NOTE: Executing RunQueue Tasks
WARNING: The postinstall intercept hook 'update_icon_cache' failed (exit code: 127)! See log for details!
WARNING: The postinstall intercept hook 'update_font_cache' failed (exit code: 1)! See log for details!
WARNING: The postinstall intercept hook 'update_pixbuf_cache' failed (exit code: 2)! See log for details!
NOTE: Tasks Summary: Attempted 2922 tasks of which 770 didn't need to be rerun and all succeeded.

Summary: There were 3 WARNING messages shown.
hemeng@ubuntu:/QorIQ-SDK-V1.6-20140619-yocto/build_t4240qds_release$

想问下大神这是什么意思，为什么会出现警告