Ok decided that i would delete the contents of one of my cards, when it was plugged in to a card reader. Then i put it back in the 404 and all the stuff was still on it. So i put it back on the computer and filled the card with large samples, then loaded them in some other banks, then continued to deleted the samples when plugged into the computer and load more and more samples on the sp.

I know its probably not safe, cause i could lose all the data, but yeah im working around the size of my small 128mb cards.

Oh and a quick question, How much is a brand new 303 worth. Cause a store near me is selling it for AUS$ 500. But it has no cards. Are the cards hard to get?

if you are copying and pasting then that might explain it. what i would do is
1.make a folder with the project name.
2.with the card reader move the roland file into that project folder.
3.delete roland file on card(i think it's still there actually).
4. format the card in your 404
5. go back to reader and import files from pc.

aside.
if you format the card and then leave that fresh untouched roland folder in a 'blank' project folder then you can do it like this;
4. load blank project folder onto empty card
5. import wav files from pc
this will cut down on the card juggling.

hope i understood your question.