Release 10.1A: OpenEdge Development:
Progress 4GL Handbook

Setting your Propath correctly

The Propath is the set of directories Progress looks in to locate procedure files to run. Configuring your Propath correctly is essential to good application performance. The more directories there are on the Propath, the longer it takes to search for files. Larger directories may take longer to search than smaller ones, depending on your operating system.

You should order directories by their frequency of use. Put the most frequently used directories first.