External Driver/PSP 9.01 Problems

I have PSP 9.01 and just bought an external drive to put all of my tubes. I followed the instructions (I think) and backed up all of my tubes. However...when I go to open one of my tubes in PSP from the external, I always get the error message "This is not a valid PSP file" and when I try to browse and look at all the contents of the files (my tubes) they no longer show as thumbnails in PSP. I checked the file preferences and that was seemingly in order. And when I open a tube from my C drive, they open in PSP as they always did. I'm SO bummed out. I thought this was the answer to the little room I had on my C drive to my extensive tube collection. Can anyone please help??
Thanks so much, in advance.
Jill

I have been suffering form disk space on my C partition, and have been running disk cleanup to remove old unsued files. I found that the browser accumulates a lot of off line content, too. I hadn't selected to remove tthat since it didn't appear to do anything. I tried it and let it run to completion, and increased my file space by 4 GB.

Along with another problem, I was looking at a new hard disk. My hard drive is fine, and the problem is related to some thing else. A 250 GB 7200 RPM was about $130. We were going to Ghost to the new drive if necessary.

You might look at the external drive letter when it is running. It may be dynamically assigned, and not always match the PSP assiogned location.

Rich

I haven't seen a problem in my system. My external drive is a DVD burner, and I haven't seen a problem.

you might ask in the off topic section and mention the drive you are using.

Rich

Thanks to both of you for replying...I'll check both of those things out. I do use Clean Up to get space back on my C Drive, but I have gigs and gigs of tubes/jpegs- so I really needed to move them all to an external. I'm off to see if your suggestions work. Thanks.
jill