Decker - this is why some of us have numerous corporations, etc.
The 25% cap is a personal cap imposed by the law. In other words, it doesn't matter how many corporations pay you, your contribution to a SEP is still capped for you, 33333...., at 25% of your annual net income. That 25% is capped at $46,000 for 2008.
Are your contributions in excess of $46,000?
If they are, you have a problem.
Here's some more free advice.
If you're doing what I think you are doing, you are in big trouble. The DOL will pull your tax breaks retroactively and impose penalties on you...if they find out. And eventually, they do.