Explorer problems with 3-column liquid theme

I wanted a three-column liquid theme so I used “Tulip Time” as a starting point and modified it for my blog. The themes (I made three plus a plain vanilla 2-column theme) work fine in Mozilla.

But I am told that the three-column themes don’t work in Explorer. The complaints are usually that the right sidebar, sometimes the left, covers up the central text. I have a Mac and no longer have a working copy of Explorer so I can’t even review the problem much less diagnose it.

Has anyone else had this problem with Explorer? Is there a simple solution? Thanks.