Can those who are running without issue confirm if they are using Mixed mode or Only G mode for the AP's.

This is the cause of the problem which i am having with my DDWRT router and i think the same that everyone who is having a problem here is facing.

It simply cannot even see the router when it is set to mixed N/G mode.
The bug link is https://bugs.maemo.org/show_bug.cgi?id=10893.

Unfortunately the person who raised it simply closed it because he changed to openwrt instead of following up to close it for ddwrt.

The issue could be ddwrt's fault as to how it implements signalling for moxed mode or how N900 reads it.