This can be due to ambiguous 2 compilers in path and happens reproducibly in Ubuntu / Mint and other distros.
As a result nothing ever compiles, e.g. IDE recompile is impossible. Meaning: this problem is a real
showstopper, completely
ruins the experience. Maybe Laz should diagnose this on startup (just call the test function under project options) and issue a stern warning. I ran into this in about 15 installs or so.
The easy solution:
wiki