Annoying gap between left column and center box

Hi, thx in advance for helping out

I recently changed the width of my site reeselectronics.com because i wanted a 4 column grid. that went well on the main page. however every other page seems to have a gap between the left column and center box. i tried messing with the stylesheet mainwrapper and tpl_main_page but with no luck. also appears in categories. here's some pages

http://www.reeselectronics.com/ (no gap)

http://www.reeselectronics.com/reviews.html

http://www.reeselectronics.com/audio-c-13.html

All help is greatly appreciated.:lookaroun

Update: even tho i changed the width in css. doesnt seem to work with Internet Explorer neither:

#mainWrapper {
text-align: left;
width: 900px;
vertical-align: top;
}

Update: i was able to remove the gap between the left column and centerbox by manually editing the width in tpl_main_page

Before:

After:

However i am still having a problem with the width in ie. again internet explorer is not affected at all. and the alignement for the whole site is slightly to the right. but centered in firefox.

PLEASE HELP:cry: