I am now going to ask you a question that you might feel is stupid and unnecessary, so please don't consider me rude, but I want to rule out every possibility of errors here as this behaviour is something I haven't heard of before. Also since you get errors on both 2.30 and 2.32, both web and USB, the probability of both files being corrupt for you alone seems low:
You have extracted the bin file inside the zip file and used that file(bin) when trying to update? On the download page 2.28 was the last file using the raw bin file format, from 2.30 we put the bin file inside a zip file as zip files have crc(checksum) which assures you download a non corrupted file.