What I wonder is if you used the build scripts located in scummvm\backends\platforms\symbian to build or if you have made your own symbian port.
The perlscripts creates all mmp files with the correct source files from the makefiles.
This is what should be documented in the wiki page but currently is only somewhat documented in a readme in the symbian folder.
Also I think you are using the standard Symbian SDL port, that does not contain bugfixes needed for scummvm (recursive mutexes) and not any adoptions for general device support (UIQ3, S80, S60, S60v3, S60v5).
My homepage is
http://www.anotherguest.se and there you can find my version of SDL for symbian.