tableless css based page displays ok in IE7 not in IE6

[sandra21]

please see http://dreamtech.awardspace.co.uk/ in IE 7 or firefox 3.0.6 - it displays fine. but in IE6, the 2 columns on the page display one below the other. i assume its something to do with the css. can you help me?
the css files are http://dreamtech.awardspace.co.uk/style.css and http://dreamtech.awardspace.co.uk/layout.css

also the page had a line <?xml version="1.0" encoding="utf-8"?> right at the top which i had to remove because it showed the error "Parse error: syntax error, unexpected T_STRING in /home/www/dreamtech.awardspace.co.uk/index.html on line 1" when i hosted it on awardspace. does this have any impact on my problem. if i remove this line, do i have to add some other line to my code to make it proper.
thanks for your time and efforts.

[MidiMagic]

The xml line is not necessary, and causes errors on some browsers.

Look for styles containing both a size style (width, height) and a nonzero surrounding style (margin,. border, padding). These can make things wider than 100 percent, causing the column to go down.

Look for anything wider than the page.

Check the page for W3C validation.

[sandra21]

thank you for your help. the problem was in style.css. i changed the line #page3 #content .col_1 .indent { padding:0 60px 0 28px;} to #page3 #content .col_1 .indent { padding:0 25px 0 25px;} and it worked fine