By PS I guess you'd mean the PlayStation Portable? It isn't available in the UK yet so I wouldn't know how to fix it, though if it has an error, send it back and get a new one Only option really, since that doesn't seem normal.
The colour palette probably isnt set to RGB... which might cause some problems if its set to another format that won't support tools like that. I think its Photoshop I'm thinking of...yeah I'm pretty sure. Should be in one of the menus at the top.