I got this error while working on an upgrade to NAV 2015.
I had just remove a custom function from table 37 (Sales Line) because I had moved it to a separate codeunit (to simplify the upgrade process).
When I tried to save the changes to the table with CTRL-S I got the error above: Internal Compiler Error 0000000d.
I searched online but couldn’t find anything.
Finally, I tried to compile the object from Object Designer after saving it without compiling, and then it gave me the proper error message: you have specified an unknown variable.
Then I found the culprit and appended the new codeunit name… and voila it saved and compiled fine.
In NAV 2009 it used to give you the same error message when you tried to save and compile, but I guess it’s different in NAV 2015.
Oh, well… problem solved.
I hope this is useful!