> If on the other side problems with "@responsefile" are only occuring
 > in more rare situation -- can anybody tell me how to provoke the
 > problem?

I was compiling an application using LablGTK to native code (using 
MSYS). AFAIR the linker invocation contained quite long list of 
libraries and ocamlopt decided to use responsefile. I got some 
incomprehensible error message (and only then discovered that I have to 
use Cygwin tools). I have no idea whether the problem with MSYS tools 
still persists. When command parameters were short enough they worked 
seamlessly.

Dawid Toton