First a big thanks for DirtyPCBs! Great service!
The last few days I tried to upload my zip file but every time there was an error about a missing outline file. Tried different settings in Eagle 7.5.0, viewed the file in various viewer and other pcb shops all ok.
Long story short: If zipping the files on a mac omit the resource files!
Maybe this helps other people who struggle with this.
philipp