when i open a map in arcexplorer, the symbology changes to exclamation marks, what could be the problem
Did you use some special symbology that might not be available in Explorer?
Jacob,
If you are using an ArcGIS Layer in ArcGIS Explorer it may be that Esri Fonts are not installed on the computer. You could try installing the ArcGIS Explorer Fonts Expansion pack.
http://gisupdates.esri.com/ArcGISExplorer/Build2500/ArcGISExplorerFontsDownload.exe
Mark
I agree with Mark, most often in these scenarios, either the Esri Fonts are not installed or not installed correctly.
