ACR-View 6.x requires either .NetFramework 1.1 or 3.51 (or higher).
The installer for Version 6.1 only checks for Framework 1.1 and flags the user if this was not installed.
This has been updated in the installer for ACR-View 6.2 which now checks for either 1.1 or 3.51+. If missing, the installer will prompt the user to install 3.51(or higher).
Framework 4.x includes everything that 3.51 has. Most Win7 PCs include 4.x, so there is generally no need to add 3.51 when installing ACR-View 6.2 on a Windows 7 PC.
When using Windows7 (32 or 64-bit) we recommend that you use 6.2 as that includes Windows signatures and checks for the later versions of the .NetFramework.
jan 31 2012 JW