In the "give a man a fish, feed him for a day; teach a man to fish, get rid of him for the whole weekend" vein,
g++ --helpshows compiler options. The g++ -v option helps:
-v Display the programs invoked by the compiler
Look through the output for bogus paths. In my case the original command:
g++ -v "d:/UW_Work/EasyUnit/examples/1-BasicUnitTesting/main.cpp"
generated output including this little gem:
-iprefix c:\olimexods\yagarto\arm-none-eabi\bin\../lib/gcc/arm-none-eabi/4.5.1/
which would explain the "no such file or directory" message.
The "../lib/gcc/arm-none-eabi/4.5.1/" segment is coming from built-in specs:
g++ -dumpspecs