[PB] Perplexing behaviour

[Hector Ignacio Macedo]

I have a G4 PB into which I saved the documents of my older computer,  
but now when I try to open almost any file (mopst of them where  
created with Text Edit, but there were other apps too)
the problem is when I try to open them, a dialog comes telling me  
that the document is used by the system and it can not be opened. I  
already tried changing ownership and repairing permissions, but to no  
avail.
Can anyone give me a hint as to what's going on and what to do to  
solve this problem?

Thanks a LOT for any help.

Hector