Wordpress Wishlist Member Classipress Theme

Have coded and developed a site using Wordpress, with the Wishlist Member Plug In, and the Classipress Theme. Am having issues in all browsers now which leads me to believe there is a php error somewhere. I have attempted to do a fresh installation of Wordpress, disable and delete plugins, change theme and also recreate the database, and each time I continue to get the same error. The errors are as follows: Google Chrome: Error 324 Firefox: Prompts download of .php file, "You have chosen to open". Internet Explorer: Blank White Screen. This doesn't happen every time that a link is clicked, it can vary from page, timeframe, etc. And is not happening with the same link every time, it happens both on the normal site and also in the admin area of wordpress. Although it does seem to happen more often in the Admin section of wordpress. I am looking for an experienced php developer to solve and fix this issue. Budget is around $50 as I know for an experienced php developer that it should be a reasonably easy fix, although I am willing to pay more if it can be fixed as soon as possible. Thank you, and I look forward to hearing what advice/ideas you may have on this issue. You can view the site at [login to view URL]