Error comes up when moving files onto psp!

[Fireking300]

I get this error when I try putting files on Memory stick 2 GB
This request could not be preformed because of a I/O error!

[cheema201]

perhaps your memory stick is a fake...

where did you get it from and wat brand is it??

[Fireking300]

It is real I got it from store the error was the psp for some reason i Have 2 seperate ones and i tryed with old Fat one and then I tryed it with my slim It was a problem with fat PSP i guess