Hi, I just tried to export and use a different project with CoIDE, and had similar issues. The project brings the same error as you reported. I tried to update the version of mbed to v92, but still same bug. I know they fixed this bug in latest mbed, but problem is v92 does not have this fix in yet. I got mine to work by using latest mbed-src. Can you try this:
1) Right click on your project, and select "Import Library.." > "From Import Wizard....". Then select "mbed-src", and import it. I imported it as a library, not sure if as program will work the same.
2) Now you should have the latest "non release" version of mbed (Dec 11). This should have the bug fix in for compiling offline.
3) You now have mbed and mbed-src in your project, BUT should only have 1. Right click on mbed, and delete it, leaving only a single mbed.
4) Now try to export your project for GCC ARM, CoIDE or emblocks, it should work.
Sorry if this is a double post. Just posted something, thought it was on forum, but I accidentally posted it in "Questions": http://developer.mbed.org/questions/5252/Errors-building-STM32L152RE-mbed-project/
Not sure why there is a "Forum" and "Questions"? I will stick to forum in the future.