Symbian development isn't very friendly. You'll just have to get used to it (or do some other type of development).

It means simply that the build tools want to build an object file but can't find all of the source files needed to do it. Consequently the tools will attempt to make the missing files but will then discover they don't know how to do that, hence the error message about not having a rule to "make target". The message can happen for a number of reasons. It could be your build files (bld.inf / project.mmp) are wrong somehow or it could be that the build is messed up. Or it could simply be that you've forgotten to include a file that's needed.

Try doing a completely clean build and see if that solves the problem. Another possibility is that it's just Carbide. Personally I only use the carbide IDE to do emulator builds: for a target release I always use the command line because I've never really trusted carbide to do builds properly! So try using the command line to do the build and see if you get the same error.