pdf creation out of admin panel

hi at all,
is there a way to create pdf out of the admin panel? i use wp 2.3.1 German edition and i write an adressbook plugin. it works fine, so i would like to create and download a pdf file. i used the fpdf class and create a pdf. it works well, when i use the parameter to write the file on server, but when i would like to download it directly by creating the file, server comes with the error –> header output allready startet… a.s.o.

did everyone of you have a solution?

best regards thomy