Sorry, that Howto is way out of date... It was written back in the OS2005 days, when debian or slackware arm binaries were compatible with Maemo.

Since the release of OS2006 and the switch to armel binaries this doesn't work anymore. Software has to be recompiled for Maemo and is best installed from repositories, as TA-t3 pointed out. I really must revamp the installation part, as I guess no one in their right mind would run OS2005 on their 770 nowadays, and N800 users don't even know what it is/was :-)