horqua,
Am I correct in assuming that you are working with PM over a netwrok, and that O:\15C is a mapped drive? If so, a word of warning.
Working over a network with PM (or any DTP app) is a corrupted document waiting to happen. PM is like an advanced relation database, and working on files over a network can cause corruption to your document index. I do it myself, and know many people that do work over a network out of necessity. But if you must, here are some tips.
First, copy all files locally, edit locally, and then copy back to network. Editing over the network removes many of the built in error corrections that Windows performs when working locally. PM has no built in error correction schema.
Second, save, save as, save smaller rather than save faster, and make sure you have redundant back up copies. Once a document gets corrupted, discard it and revert back to the last good copy you saved as.
Also, working locally you will find work much faster when editing complex projects.
good luck