Problem loading CSO files

I posted a while back about my issue with MGSortable Ops, and that ended up working fine in CSO format. However, I have a new problem. I have backed up several UMD games using Booster's UMD access program, saving the ISO files directly to my hard drive. I have converted all of these games to CSO in the same manner as MGS, but although they show up in the XMB with the trailer playing in the icon and all that, they will not start. I also tried an RPG that I downloaded a couple of weeks ago, which used to work, and now that won't run either! I formatted my memory stick a couple of days ago, so I'm thinking I must have erased an essential program for playing ISOs. What program might that be? Do you normally need additional software to run ISOs in 3.03CE?

I dont belive so, I might be wrong though, because I run at 3.10 oe, Maybe you should try updating a little more, unless you really want to stay at 3.03oeC.

Well, I didn't really have a specific reason to use 3.03, I just never bothered to upgrade after I modded my PSP orignally. I'll try it and see how it goes.

heh, I feel dumb. I never bothered to check if I had a UMD inserted! After much tinkering last night I remembered I had to do that, so now of course all my images work fine, much to my relief.