Error: Function MARA_EAN11 blocks material...

Hi, does anyone knows how to use the function module MARA_EAN11? Every time I use it, the message WE225 ("Material & currently blocked by user &"), but i checked and nobody exept me were using that material...

It seems like something remains blocked after using that function...

Please let me know if someone got the same error... and solved it.

Greetings.