Hi Semjovi,
You're right, you have to use LV 7 in order to synchronize two 5122. The synchronisation example for the 5122 is only installed when you have LV 7. The reasons are:
The PXI-5122 is based on a new modern architecture called SMC. This architecture needs some drivers which works only with LV 7. Check this for more informations concerning the SMC architecture: http://zone.ni.com/devzone/conceptd.nsf/webmain/63CA1E64DA2AAA3486256DE90003F124?opendocument
To your Error:
The additional SW drivers you have are the correct ones (VISA,IVI,..) so I would try to uninstall NI-Scope and reinstall it again. This helps in most cases. The NI-Scope 2.6 installer detects automatically all NI SW versions which are on your system and installs support files for them.
So you'll have support for LV 6.1 and LV 7.0 in your case.
Hope this helps.
Regards,
Luca
National Instruments
Regards,
Luca