LX51: Fatal Error 250 (Code Size Limit)

Information in this article applies to:

I receive the following error when I link my project:

Fatal Error 250 Code Size Limit in Restricted Version

I have the real (not the evaluation) tools and I've checked all the settings and everything seems OK. Why am I receiving this error message?

There are several reasons for this error message.

Make sure that you are using the evaluation tools. Click on Help -- About in the µVision IDE and look for your serial number. Note that you must have a project open when you do this. If the IDE reports that your serial number is EVAL VERSION (or something similar) then you need to purchase the tools or request and install a LIC for your computer).
You may have an OBJ file that was compiled or assembled with the evaluation software. Rebuild (re-compile and re-assemble) all of the files in your project. This will solve the problem in many cases.
If you are using C51 V6, you may need to update your software (see below).
You may have a DK51 kit. The DK51 does not include the full version of the extended linker, only the evaluation version. The extended linker is only available in the Professional Developer's Kit (PK51).