[fpc-pascal] Pascal data flows

[poof65]

Hello mailing user.
I'm a poor french guy who had a little problem ;-)
I've read in a book that it was possible to redirect data flows to files.

After doing my research on google, i've found a webpage talking about it.
http://www.ictp.trieste.it/~manuals/programming/sun/pascal/lang_ref/ref_io.doc.html#327

I've tried to make a little program with theses examples.

program test (output);
begin
        rewrite(output, 'test.txt');
end.

During compilation with FPC v1.9.8 (under windows xp sp1), errors occurs.

testing.pas(3,35) Error: Incompatible type for arg no. 2: Got "ShortString", expected "LongInt"
testing.pas(4,4) Fatal: There were 1 errors compiling module, stopping
Error: Error during compilation

In your opinion, what's the problem ? have i forgotten to include a unit file ?
Thank you for reading all my problem.

PS: i'm sorry for my bad english and all mistakes in my text.