Building a framed box like in this thread would be more than adaquate to support a few hundred gallons of water, let alone 90+ stand:
http://archive.reefcentral.com/forum...and+calculator
Jade, if you're worried about it, make the box a little bigger all the way around, it'd be like having it on your floor. Or you can use the thread above to help you build a new stand. The cost of 2x4's isn't much, and you can build it to whatever dimensions you want to accomodate your needs. If you have a crawl space/basement, if your tank rests on 2 or more floor joists, you should be plenty fine, especially if you're near a load bearing wall. Just make sure you do whatever you feel is in your comfort range.