What happens if you compile a program on the command line? I.e., create a file called hello.pas with just this in it:
begin
writeln('hello');
end.
Then open a terminal window, go in the directory with that file and type "fpc hello". If that gives a similar uninformative error message, try executing "fpc -a -s hello" (this tells the compiler to create a script that calls the assembler, instead of calling it directly from the compiler) and next execute "./ppas.sh" (that's the generated script).