In SharePoint you may run across this specific error, and not know how to proceed. When an error of this type is thrown make sure to locate the specific SharePoint web front end (WFE) server you are using to generate the error. In theory all WFEs should have the same content. If you are not sure of which WFE then all SharePoint WFEs that are serving pages need to be modified.
First, look into the ULS for SharePoint typically located at:
C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\LOGS
You can use the Microsoft MSDN tool called ULS Viewer to sort through the various log files. The log files are in the file structure as follows:
An example would look like:
You want to sort the logs by the Date Modified attribute, and open the appropriate log file that was created when the error occured. Search for any errors, or references to your page that has the error. This might give you a clue as to the problem.
Next, take a look at your Windows Application Event logs during the same time frame that the server threw the error. You can find the Windows Application Event logs at:
Start>Administrative Tools>Event Viewer>Windows Logs>Application
Again, remember to sort by date, and track down any event that would have been triggered at the time you generated the error.
Another important place to look at is the actual page that is given during the error. A typical error page will look like this.
This is telling you that it wants to show you more information about the error, but it can’t since you are not at the correct location. To change that you have to modify some values within SharePoint’s IIS web.config file. There are a couple things to caution you about:
To get to the appropriate web.config file open your IIS manager.
Start>Administrative Tools>Internet Information Services (IIS) Manager.
Once that is open you want to ‘explore’ the physical file structure of you SharePoint site in IIS.
Once that is open you will see something like this…
Caution: Remember to make a copy of the ‘web.config’ before you make any changes!
Do a search in the web.config file, and look for the ‘customErrors’ tag. By default the mode will be set to “RemoteOnly”. change the value of the mode to “Off”.
At this point save, and close, your web.config. As soon as you save the modified version of your web.config this will trigger an IIS reset of the web front end you are working on. You will want to trigger the original steps to generate the error page again to will show you more details as to what is triggering the error.