This is a strange issue.
Can you tell me what you are trying to capture from your screen? Is it a DVD output?
Are you using version 10.4.11 still?
Have you tried using the Grab application (in your Applications/Utilities folder)?
well.. iv restarted the computer and now everything is ok
but im going to answer your questions anyway
im still 10.4.11
iv tired with grab and the result was everything
thank you Rounik as always!!!!
Glad it's resolved! A restart is one of the best things to try first if something quirky happens... Although I must admit I have never heard of this issue before - so couldn't say what may have caused it.