Another thing to consider for maintenance. UNC paths are nice, but server names do change. Store them in a table where possible to reduce the number of code changes you'll need to make when that happens.
We are having the same problem with a DTS package setup to truncate SQL tables and transfer the data from an access database to the SQL tables. When running the package from my machine the package can be excuted. But at some point the settings for the filename and tables to populate are lost or reset. This is a sporadic. Also after successfully running the package manually and then scheduling it also fails giving invalid path errors. The server on which the actual package is saved gives a catastrophic error when opening the package properties. Some guidance on this would be greatly appreciated. Thanks