Tried updating both apps via Platform updater both had download failures. Manually went to each download and downloaded ok. Went to install each and they both error out with write errors. I then ran each as administrator and both installed properly.
Win 8 64 bit all updates writing to a 250gb usb HD 125 as linux partition and 125 for PortableApps. Vipre Internet Security 2013. In fact on the Maxthon I even had to allow it past the Windows nag screen about allowing it. I have full uac control in fact even to point the UAC is sett o low
They just had the MD5 wrong.
Neither of them require admin rights to install. I just downloaded fresh copies and installed them without issue on Win7 with UAC enabled. Note that Maxthon is not digitally signed by the publisher. It is up to them if they want to but not required.
Sometimes, the impossible can become possible, if you're awesome!