If an error occurs in mojoPortal content management system, you generally will only see a page that tells you an error has occurred. This is because the site is configured to only show a friendly error message and not error details. It's a bad idea to share any error information with the public, as hackers may use this information for further attacks. In order to troubleshoot the error, you first need to know what the error is.
Checking the mojoPortal Log
mojoPortal logs all unhandled errors, as well as some handled errors and info, in the system log. You can view the log from Administration Menu > System Log. The log itself is just a text file located at /Data/currentlog.config, so you can also download it and read it locally using a text editor.
The newest errors will be at the bottom of the file. On a new installation, its normal to log a lot of errors at first because the database is empty until the setup page has run.
If there is nothing in the log or the file does not exist, then it's usually an indication of a site where the file system permissions are not configured correctly. The web process must have read permission on the whole web root folder tree, and it must have read/write on the /Data folder and all files/folders beneath it.
If the log has a bunch of stuff in it and you are trying to find a particular error, the best thing to do is clear the log, cause the error, and then look in the log again. You can post an error in the forums if you don't know how to resolve it and someone may be able to help, but please don't post large chunks of your log, try to find the specific error and post the error detail only.
Disable the Friendly Error Page and Show The Real Error
It is also possible to disable the friendly error page and have it show the error detail in the page. You can do this by editing in the Web.config file in the root of the web. Look for this:
<customErrors mode="RemoteOnly"... and change it to this
After resolving the problems, it's best to change the customeErrors setting back to RemoteOnly, so that error details are not revealed to the public.
Once you can see the error, you may have enough information to solve the problem. If you are not able to solve the problem yourself, you can post in the forums and include the error detail.
Note that if setting CustomErrors to Off does not show any error detail, typically there is an error in the Web.config file so it cannot load the Web.config file, therefore the setting to show the error is not applied. A very common cause of this is if the site is configured for a different version of the .NET framework than what is needed.