[TYPO3] Menu images failed to create

[Alexander Newald]

Hi,

I installed the latest stable version of typo3 and all works fine except the 
creation of menu images on the fly:

convert: UnableToOpenBlob
typo3temp/temp/6895512abb8cf080bbf82236214b9f01_maskNT.gif: No such file or
directory, referer:
., referer: http://...
convert: UnableToOpenBlob
typo3temp/temp/6895512abb8cf080bbf82236214b9f01_maskNT.gif: No such file or
directory, referer:

The temp dir is existing and some other files are in it.

What did I miss?

Alexander Newald