Does this work?
I tried installing 4.15b over 4.1, but now a number of menu choices come up
An error occurred Unknown action
The choices that produce this error (from the Blog admin panel): Manage: Pages Design: Templates Preferences: General Preferences: Publishing Preferences: General Preferences: Publishing Preferences: Entry Preferences: Comment Preferences: TrackBack Preferences: Registration Preferences: Spam Preferences: Web Services Preferences: Custom Fields Tools: Plugins

OK, I tried the 4.15 Professional Pack Beta 1. Same results.
Any ideas?
I tried it over Pack 1.1 (which comes with MT 4.1) and works fine. I'm also testing tried 4.15b4 over 4.15 Professional Pack Beta 1. Works fine too.
Hmmm. I wonder why I'm getting this error then. I even tried switching to a new database and letting mt recreate all the tables - same result.
Maybe I'll have to wipe everything and start over. Alas.
Is there a way you could include a screenshot so that we can see what is going on. Generally speaking this should work. I have done it in several places, including my personal blog. If it is not working I would really like to know why.
ok, that didn't work.
How about this?
http://plainfieldchurch.org/images/unknown.png
Beta 5, same deal.
You're not alone Cindi - same problem here. I was able to do the Beta 1-3, but Beta 4 wouldn't install (could not update due to custom fields used from the professional pack) and Beta 5 installed but wouldn't recreate files on the hard drive (everything looked good, but making a new blog only updated the main index - which then linked to a page that didn't exist). I rolled back to Beta 3 but plan to do a fresh install of Beta 5 later today (I'm testing, so I can easily wipe everything out and start fresh).
My thoughts are the issues are from the professional packs. I also had a problem with Categories I created - I couldn't remove them from any of the entries when I upgraded from Beta 2 to Beta 3. I'll update everyone after my fresh clean install. I like the changes the beta's have brought to the admin interface.
Early betas of MTOS could not be dropped on top of MT Commercial. Doing so could result in problems in upgrading down the road as the meta data storage system was still in flux, and MT commercial (because of Custom Fields) relies upon that meta data storage system extensively.
In general you should never install a later version of MTOS over an earlier version of the paid product. MTOS is the core of MT, which the commercial/professional pack relies on. Upgrading the core without upgrading those components that depend upon it could therefore introduce instabilities into your entire installation.