Images Wont Upload Anymore

Im using CS cart 3.06 on several sites all on shared hosting.

My host has updated the PHP to 5.3.29 as its the lastes version, this i think has now stopped me uploading images to my websites.

When i try to upload images i get the error…

It is not allowed to create/upload/rename files of the application/octet-stream MIME type

As you can imagine this is a large problem, its effecting all the sites which are all on seperate installs, I have not had this problem before and the sites have been running for years.