ArcReader 10 cannot coexist with any previous version of ArcGIS Desktop. If you run the Conflict detector that comes up on the splash screen when you insert your disc (or run 10UninstallUtility.exe) it will detect your 9.x installation and won`t let you to install v10 ArcReader. However, there is no point to do that anyway, since PMF files are version specific, ie. you cannot open a v10 PMF in ArcReader 9.3.1 (and I think it`s true vice versa). I hope this helps. Zoltan
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