It sounds VERY much like #3, boox,
The question for Blume is "who is providing your Internet access?" For instance, AOL is notorious for limiting the size of attachments and downloads and is also hopelessly stuck about 5 years behind modern file sizes.
It's not Internet Explorer, nor is it GAC, Blume. It is your Internet Service Provider. Check with the ISP and see what restrictions they impose. You may have to upgrade your service or change providers in order to access larger files.
Peace, Jim (|:{>