I am looking for an equivalent of Microsoft SQL Profiler for a Progress 4GL database.
Maybe. It depends on how "equivalent" you need your solution to be.
If you are looking for general performance data then options include:
If you are specifically looking for something along the lines of "explain plan" then you probably want to be running OE10.2B or better and look into the "client statement cache" feature.
If you wish to profile the performance of 4GL code then you might be wanting to use the "profiler" feature of the ABL. You can get to that via the -profile startup option or by using the session:profiler handle within a session.