bingo!

'apt-get install qt-components-10-com-nokia.meego-1.1-compat' still didn't work, but after nelisquare was installed, 1.8.1 installing and logging in with the PIN was no problem. I removed nelisquare again and tweetian doesn't seem to be affected.

This is under maemo7.2+thumb1 flavor:testing KP52. Thanks!