I have encountered this trying to backup an SQL database, I made a copy of the files onto the main drive thereby removing the top 2 folders which was enough to reduce the names to under 255.
If you want a really long boring exercise you can always open cmd and type dir c:\ /s /b > files.txt
I,m sure you realize this lists all the files into a text file which on opening you can trawl through for the longer paths.
I dare say someone will have better help. But at least I tried.