If you have recently downloaded PlanetGIS version 2.50, please update to 2.51 to avoid compatibility problems with older maps. A bug in version 2.50 caused older maps to be marked as version 2.50 upon saving, even though the Tools->Maintenance->Compact process has not been followed. This will result in a “Stream read error” the next time you open a non-upgraded map with version 2.50. To recover from this you can open and save the map with an older version of PlanetGIS (<2.45) or send me your .map files so that I can fix them. I apologize for the inconvenience this little bug may have caused.