problem in smartform translation

Hi All,

I have copied standrad PO smartform as a Z form with language as English.Now the form has some translated text in

German language and I want to make chnages to this German text.I go to SE63 and enter form name

and write 'Source Language' as EN and Target language as 'DE' and I get an error saying

'Incorrect codepage'.Pl let me know how to correct this error.