Error on Upgrades to Plugins

HI;

I recently upgraded to WP 3.0.1. I’ve had a number of plug-ins that failed upgrade. The error is normal this or similar:

Could not copy file. /public_html/sitename.com/wp-content/plugins/plug-in-name/images/print.gif
Plugin install failed.

After reading old support posts, I found the suggestion to remove the /wp-content/upgrade directory. I did and this worked for the majority of the plug-in’s.

I’m was trying to upgrade Tiny MCE and I got this error, ever after deleting the upgrade directory. So I un-installed Tiny MCE and re-installed it only to get the same error message again.

Any ideas what else I can try?

Thanks
Jamie