Parameter is Incorrect

Just launched our new wordpress site tonight. We are not wordpress novices but this is a unique problem. Heres the cliffs notes:

– Website @ http://www.infosurv.com
– This is a website redesign project we launched this evening.
– We have set up redirect rules so that links from the old site link to the new. Here is an example of a redirect: http://www.infosurv.com/about_us.htm
– If you open (or restart and open) Safari and type in that address you get a generic “Parameter is incorrect” error.
– Now, while you are sitting on the error page click refresh and now the redirect works.

What we have gathered is that that Safari (and Firefox) need to load the Index.php page first BEFORE it can load the URL the redirect rule points to.

Any thoughts/ideas on how to fix this?