Thanks a bunch for your efforts jester and rpertusio. I really do appreciate it.
rpertusio: I can't just make the image 30px wider, as it distorts the image and it puts me over the 780px width constraint.
I fixed the modules on the right hand side (that no one knows what I'm talking about!

) These 'modules' are the boxes on the right side of the website...the site search, news headlines, sponsors, etc. Using <DIV> instead of <SPAN> and changing the doctype to "-//W3C//DTD HTML 4.0 Transitional//EN" the black header for each module now spans the entire width in both IE and MozillaFirebird. (These are the two I have installed at the moment for testing).
And I'm 99% sure I've pinpointed the problem with the gap in the header: the 'padding' attribute. To illustrate the problem, imagine a simple one cell table:
Ok, so you have a table. You set the width of the table to 500 pixels (keep in mind we're using a style sheet). Now you want some padding in the cell so the contents are not touching the border of the table. Let's make it 10 pixels on each side.
-In IE, the padding is layed around the inside of the table and the actual area inside the table is decreased (real world example: putting insulation inside of a room, decreases the area of the room by the width of the insulation). So now the area inside the table where stuff can go is now 480 pixels wide (10 px taken off each side). THIS IS HOW IT SHOULD WORK!
-In Mozilla, the padding is still layed around the inside of the table, but Mozilla says "Wait a sec! I've lost area inside the table! (remember the insulating example?)." So to combat this, Mozilla widens the table until the area inside is equal to the set width. In the real world example, this is like tearing down the walls and building new ones, leaving enough space for the insulation so you still have the same amount of floor space.
<Cyberlore wipes the sweat from his brow>
Now, I'm looking for a solution. The padding problems occur in my <DIV>'s. So with my website, Mozilla is making the modules 10px wider than that should be (turns them into 160 pixel wide boxes) due to a 5px padding on each side. The break in the header occurs because the content portion of the site (the middle) is set for 7px padding on each side (in the case of the content section, i'm just using the style id in the <TD> tag, no <DIV> is used).
Wow, I realize that's a ton to read through, but I just want to make sure I get the point across. I'm really baffled as to my Mozilla seems to handle it this way. If anyone can help me out with my dilema, it would be very appreciated!
(LINK:
http://www.wors.org/indexphp.php. If that is dead, I've launched the site, in which case, just visit
http://www.wors.org)