Error255 on compiling !

Hi all ..

It's been a long time for me reading and learning from this forum .. i really like it ..

but i have a problem . i think it is too silly .. but it's still a problem to me ..

I use NIOS II IDE 5.1 .. i have a c code with its 'makefile' .. I open an advanced c/c++ project to be able to add me own 'makefile' .. I added my files ..

When I choose "Build Project " it gives me an "error 255" for all the files to be compiled .. and compiles nothing !

Can any1 help ..?

Thanks in advance !

Yours,

Tarek