Coding errors (or coding_exceptions) are problems that are probably caused by incorrect code. For example a plugin that does not communicate correctly with Moodle core.
These errors are normally not caused by incorrect user input or temporary problems like the connection to the database server being down.
As with all error messages, it's a good idea to search moodle.org and the tracker to see if anyone else has reported the problem.
Block type ... has been disabled by the administrator
See the discussion Coding error detected, it must be fixed by a programmer: Block type admin has been disabled by the administrator. for a possible cause of the error plus solution.