Did you copy/paste the command? I tried the command with -s tag (to simulate it, not to install) and it said that the file was found from downloads.maemo.nokia.com.

If I misspelled the filename, I got the error that the version was not found. Can you try to copy/paste the command and copy/paste the contents of the x-term then here? If the command is right, and you still get the error, you should check that the standard nokia and ovi repositories are enabled in HAM.

BTW I'm not sure, but you might want to read the whole thread again, where the quote came from, as there might be some other packages that have to be downgraded also. They might get downgraded automatically with the BME, but I can't be sure about this. There is always risk of screwing up your N900 when up/downgrading core system packages manually.