EasyBlog problem uploading images: "Invalid Response from Server"

We're unable to upload/post any images on the blog and are getting the "Invalid Response from Server" error. I've read the other posts related to this error and haven't been able to diagnose it on our own, even though I've had our UI developer looking into it. I've set up EasyBlog on other GoDaddy-hosted sites with no issues.

We host our own site and our security guy has it pretty locked down...I'm doubting he's going to want to open it up for FTP access in order to diagnose. Do you have any other ways you can help with this issue? A list of areas we might look at, for example?

Thanks for your help.