Title: Error: Stsadm AddSolution failed to extract the cab file in the solution
Details: When tried to addsolution using stsadm command, some times the above error is experienced. Now, what to look for?
Step#1: Extract your .wsp file
Step#2: Check the contents and make sure there are no duplicates ( files or resources )
Step#3: See if you have any files with special characters including brackets ' copy (2) filename ' so on and so forth.
Step#4: Clean up unwanted files and rebuild your .wsp.
Step#5: Addsolution this time and verify.
You should be good now.