While deploying a feature with a lot of files (200+; actually they are all the image files used in the project), I’ve used regular expressions to build the feature.xml and the element descriptor files. This is quite cool and you can actually build the files in a couple of minutes. But, as you don’t look at all the file names there are some issues that you will probably miss. In my case, I have built the WSP file with no sign of trouble. But when I was trying to deploy (stsadm -o add solution) I got the message “Failed to extract the cab file in the solution.”.
It seams that although the OS and all the WSP processing mechanism (WSPBuilder) allow, the deployment mechanism complains about special characters in the file names! After a thorough look, I found a file with a “+” in the name.
Renamed the file, corrected all the references (deployment and usage) and it everything went OK.
If you get this king of message, my suggestion is to check all the file names. Look for special characters, language dependencies (i.e. çãõáéíóú…) in the file names included in the WSP.
Hope this helps.