This error occurs if something is wrong with the setup of the application. For instance if not all prefs.inc variables are available or if the indexer.mirror42.dll has not been registered with regasm. Also when using the commandtimeout constant in prefs.inc in version 4.1.4 you get this message. This problem has been solved in 4.1.5

Run http://localhost/m42/portal/reindex.asp?key=1 to see the error message.

Be sure to turn OFF friendly http errors in Internet Explorer - Tools - Internet Options... - Advanced - Show friendly HTTP error messages