Update: alright problem is solved. This time I have used the WordPress K2 theme which turned out to be able to handle multiple columns perfectly and it has been well maintained by its creators. So do not use the 3ColumnK2 theme it seems to be dormant and it no longer works with the version of WordPress.
Just an hour ago I’ve upgraded to the WordPress 2.7.1 however the probelm is that 3ColumnK2 theme that is used as the base for developing the rmd Studio blog theme, has some issues with the recent version of WP. For example you can’t click on the arrow above and go to the previous page. Unfortunately seems like that the 3ColumnK2 project has been dormant which means I either have to fix this theme myself or redesign a whole new theme.
Anybody else experiencing the same issue? I’d appreciate your comments.