Details: is not a valid Win32 Application. (Exception from HRESULT: 0x800700C1)

I currently just installed vSphere Client, from our vcenter server. The application launches, but when I try to create a new VM I'm greeted with this lovely error. \

Details: is not a valid Win32 Application. (Exception from HRESULT: 0x800700C1)

I'm on a Windows 7 64 bit machine that is a member of a domain. What are some things I should look for?

I personally see this error a lot on machines that do not have the right .NET version... but with Win7 x64, which ships with .NET 3.5, I would think you'd be fine... either way, you should upgrade your .NET as best you can. Especially if you have .NET 3.5, try upgrading to .NET 3.5 SP1...

In fact this is from the VMware website:

The vSphere Client requires the Microsoft .NET 3.5 SP1 Framework. If it is not installed on your system, the vSphere Client installer installs it. The .NET 3.5 SP1 installation might require Internet connectivity to download more files

So do you have SP1?

Sigh... then why didn't the installer install it? Hmm...