2.0 error after posting – asking to open post.php

Hi! every time I write a new post, it takes a while after I hit publish, then I get a ‘open file’ dialog asking my where to save/open ‘post.php’ i opened it in dreamweaver and it is just a blank php file. Now the post posts just fine if I cancel that dialog, but then it just sits there on the post screen (as if it didnt post – even though it did. Now I am also having problems with ‘performancing’ in firefox, again, it posts just fine but then gives me an api error, but they do post….. this all started when I installed some plugins…. I of course, being a tard, didnt do it one at a time and check for errors, but here is my list of plugins, does anyone know if any of these are ‘known’ to cause this?

Like i said, everything is posting fine with both performancing and in the wp-admin, but it is mainly a annoyance to have to cancel out the error dialogs.

Countdown Timer 1.4
Akismet 1.2.1
Custom Smileys 2.4
DoFollow 2.1
Easy_Expand 1.1 <<cant get this to work- have to use ‘more’ tag instead
Headline Images 2.8
Link Indication 3.0
MightyAdsense 4.1
mEBuyYouADrink 0.3
Google Sitemaps 2.7.1
WordPress Database Backup 1.7
WP-Cats 0.13

thanks in advance– my blog is here – https://www.dillydesigns.com