Standard error message shown when Magento throws an error.
There is two ways to see more about how to find out what the details of the error is.
-
Locate the error in the var /log (Option 1).
-
Change the file to have the error printed to the screen (Option 2).

Option 1
When Magento throws a error it is recorded in a file. What you can do is look at the error message and it will display a number.
Like 1065941995823. This number has no real meaning but tells you what number to look for in the error log.
The error log location is [Magento root]/var/report/[random-number]

Option 2
The error can be printed to the screen. This is useful when new errors are created and you are trouble shooting a problem.
If you change the file [Magento root]/errors/local.xml.sample
to /local.xml then the errors are printed to the screen.
to [Magento root]/errors/local.xml
