Is there a maximum source code size?

[DemonBuilder]

I'm using Delphi 7 with Win XP and I've come up against a problem I
can't solve.

I want to add code to an application but when I do the compiler raises
a spurious error elsewhere in the code, where there was no error
before. For instance, if I add a procedure that contains only a
comment to the bottom of my existing source, the app compiles without
errors:

procedure TMain.RecallChecklists1Click(Sender: TObject);
begin
// this is a comment
end;

However, if I add a functional statement, such as:

procedure TMain.RecallChecklists1Click(Sender: TObject);
begin
MessageDlg('Boo', mtInformation, [mbOK], 0);
end;

the compiler raises an error and highlights a line of code somewhere
above the new procedure, where there was no error before. If I cut and
paste the entire procedure to somewhere else in my code, the error
'moves' too. Is there a source code size limit that I'm crashing? Or
does anybody have any other suggestions as to what is happening here -
I'm stumped.

Thanks in advance for any suggestions.