Well andy, I know this isn't much help, but my only thought is 'weird.' I could understand if it was the other way around, because that you might have closed down some things to run fs better. But on your ordinary account, that just weird.
Sound like you are running something on you ordinary account that block your download. Can you download from other websites, like our own? Are you running some kind of firewall or something like that on your ordinary account that you don't on your FS account.