//rant mode 1
that's what I ***HATE*** about the apps manager. The stupid repository menu! Why can't they just give us a longer list with simple check boxes to easily turn each one on or off??!?! There are just way too many clicks to accomplish what should be a simple laundry list. And why don't they make the rep list part of the near useless BACKUP function? It would be like every time you take a shower, you have to go back to every store to go get your clothes back which disappear every time you bathe. Sure, I made a copy of the list text file that I keep as part of my backup routine which I use the terminal to replace, but I shouldn't have to.
//rant mode 0

Problem solved.
Hello, Nokia software developers! Have you just graduated from the kindergarden? Or, may be, developers of Flash utility for Windows are still there?
So, when I got my Nokia 770, I started to play with some software. Installed some applications, new themes and etc. I was not playing with system things. However something went wrong. I was not able to get rid of one theme and etc.
Even worse. I could not refresh list of packages in AM. I reflashed OS with the same version and had the same error with AM. I could not use application manager to connect to repository's and install new software. I started to worry, asked questions here, tried a couple of things and with your help learned something about my Nokia. Finally, I installed OS2007_hackers_edition. And with OS2007_HE everything worked fine. Then I reflashed back to original OS and magic happened-my Nokia started to work as expected. This means that by flashing with OS2007_HE something was rewritten. And OS2006 was not completely cleaning memory while reflashing.
Thank you all for your help. And, should we expect that commercial software for commercial product would work properly? This small things are making
very bad impression of really great product. I love my Nokia 770.

@gigabites: The repository list _is_ part of the backup. On the N800 at least.

I was not backupping anything as soon as I felt that something could be corrupted. My main goal was to restore functionality of app manager. I was not able to fix this problem by using apt-get update.

I've also had this problem -- failure to refresh the list of apps (my most recent successful refresh date was 11 July). When I check Application Manager > Tools > Log it lists "osso-application-iinstaller 4.46. UI version 2" and will not clear. It's not possible for me to uninstall this app since it is required by fmradio, mediacenter, osso-ai, skype-ui, nokia-repository, and rhapsody. I have no idea how to fix this no-refresh bug. Other posts here suggest that osso-xterm (which I've downloaded) can be used to address the problem; if anyone can help me come up with a solution I'd be very grateful! It seems like a lot of N800 users are having the same problem.

Correction: here's what appears in the log after I try to refresh the application manager - installed apps repsository, before I clear the log:

osso-application-installer 4.46, UI version 2
W: Couldn't stat source package list http://garage.maemo.org bora/user Packages (/var/lib/apt/lists/garage.maemo.org_maemo-mapper_dists_bora_user_binary-armel_Packages) - stat (2 No such file or directory)
W: Couldn't stat source package list http://erinye.com bora/user Packages (/var/lib/apt/lists/erinye.com_maemo_dists_bora_user_binary-armel_Packages) - stat (2 No such file or directory)
W: You may want to run apt-get update to correct these problems
W: GPG error: http://maemo-hackers.org bora Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 5FD45CD3EA68E29D
W: GPG error: http://catalogue.tableteer.nokia.com bora Release: The following signatures were invalid: BADSIG CBFC2BECC6903E72 Nokia Internet Tablet Archive Automatic Signing Key <integration@maemo.org>
E: Failed to fetch http://erinye.com/maemo/dists/bora/u...kages.gz&nbsp; 404 Not Found
E: Failed to fetch http://garage.maemo.org/maemo-mapper...kages.gz&nbsp; 301 Moved Permanently
W: Couldn't stat source package list http://garage.maemo.org bora/user Packages (/var/lib/apt/lists/garage.maemo.org_maemo-mapper_dists_bora_user_binary-armel_Packages) - stat (2 No such file or directory)
W: Couldn't stat source package list http://erinye.com bora/user Packages (/var/lib/apt/lists/erinye.com_maemo_dists_bora_user_binary-armel_Packages) - stat (2 No such file or directory)
W: You may want to run apt-get update to correct these problems

Thought I'd throw out one more request for help -- see previous two posts. I've searched the forums and can't find a clear set of recommendations for dealing with an applications manager that fails to refresh, and it looks like other users like me (who are not skilled at Linux xterm protocol) are having similar problems. Can any of you experts lend me a hand? Thanks!

As a general observation I've been frustrated by how many times my one-month-old N800 is giving me various failure messages, often when an operation (such as moving a file) was actually successful. I'm loving the gadget but boy oh boy it so often takes me on a scary ride to buggy beta-ville (with occasional side trips to Linus newbie hell)!!

Hi,

I had a similar problem and it was caused by the following bad repository:

Maemo repository

http://repository.maemo.org/
bora
free non-free extras

I just removed "extras" and the problem was solved.