Troubleshooting the MOSS error: "An unexpected error has occurred"
Change the following values in your web.config file so that you can see what the actual error is:
1. Change CallStack="false" to CallStack="true"
2. Change <customErrors mode="On"/> to <customErrors mode="Off "/>
3. Change <compilation batch="false" debug="false"> to <compilation batch="false" debug="true">
When you are done, make sure to change these three back to its original value as there is a performance hit when these are turned on/enabled.