Uploading of new Custom Avatars Failing

[B-pLeAsE]

Uploading of new Custom Avatars Failing for all users of my community.

We recently upgraded from vB-3.8.7-PL5 to vB-3.8.8-PL1. After that users started reporting problems uploading new Custom Avatars.
When you try to upload we get the following error, "Upload of file failed". I went to Maintenance / Diagnostics /

file_uploads:	On
open_basedir:	None
safe_mode:	Off
upload_tmp_dir:	/****/********/tmp
upload_max_filesize:	64 MB

No errors occurred while opening the uploaded file for reading.

We are using ImageMagick 6.7.2-7 2015-02-27
PHP 5.4.42

Hope somebody can help with this...

Thanks!