Open IE and go to Tools\Internet Options. Hit the security Tab and select the default button. Hit apply and then ok. Try to update again.
You can also put the site into your trusted zone.
If that does not work, perhaps it is Microsoft's AntiSpyWare that is preventing the install? Try disabling protection temporarily and try again.
Scan with hijackthis and tick the boxes next to all the following entries, then close all browser and explorer windows, and hit the "Fix checked" button.
R3 - Default URLSearchHook is missing
O3 - Toolbar: (no name) - {2CDE1A7D-A478-4291-BF31-E1B4C16F92EB} - (no file)
O9 - Extra button: (no name) - {CD67F990-D8E9-11d2-98FE-00C0F0318AFE} - (no file)
O9 - Extra button: (no name) - {6685509E-B47B-4f47-8E16-9A5F3A62F683} - file://C:\Program Files\Ebates_MoeMoneyMaker\Sy350\Tp350\scri350a.htm (file missing) (HKCU)
O16 - DPF: {56336BCB-3D8A-11D6-A00B-0050DA18DE71} (RdxIE Class) - http://software-dl.real.com/3127b6b...ip/RdxIE601.cab
Netster
O23 - Service: Network Configuration Service - Unknown - C:\DOCUME~1\Chris\LOCALS~1\Temp\_instd00\NetCfgSv.EXE (file missing)