I am having the same problem...how can i download 7.8.5 version so that i can upgrade 7.4 to 7.8.5.
You need to contact customer service. Those versions have reached EOL so this may be a difficult process.
I had the same problem and here is the reply from Support.
One of the requirements of installing SolarWinds Toolset is to have Administrative privileges on the system. It is possible that, although you were logged in as a Domain Admin, your account did/does not have the necessary privileges on the local system to successfully install SolarWinds Toolset. I am guessing you worked around this by logging in as a local administrator or by disabling UAC (which allowed non-local admins to perform the required actions). Sincerely, Chris Foley - SolarWinds - Support SpecialistSupport:866.530.8040 || Fax:512.857.0125network management simplified | solarwinds.com
Did you try regsvr32 for each from CLI?cd Windows\system32
regsvr32 /s expsrv.dll
regsvr32 /s InnovaDemo1.ocx
regsvr32 /s xunzip30.ocx
regsvr32 /s xwpdlx20.ocx
regsvr32 /s sqlunirl.dll