First, make sure that you do indeed have LabVIEW 6.1 and not 6i (which is really 6.0.0). If you do, you can bypass the LabVIEW version check. Start a command prompt (usually Start>>Programs>>Accessories>>Command Prompt) and type the following command:
msiexec /i X:\measurementstudio.msi EAGLE=1
(replace X with the drive letter of your CD or otherwise specify the location of measurementstudio.msi).
Let me know if that doesn't work.
Thanks,
Tony