The error NS #262, cannot update the NSS registry backup file, may be caused by some files being set to read only or the user access privileges not being sufficient to modify these files.
The files are nssconfig.regdat and VniConfig.regdat. Nssconfig.dat is located is the database folder whereas VniConfig.regdat is located in the database folder\VNIs\_Default\
If you are not sure which folder is database is located in, you can check the Windows registry. For example,if the project name is EchelonSupport then the registry key HKEY_LOCAL_MACHINE\SOFTWARE\LonWorks\NSS\Configuration\EchelonSupport \Directory Name will show the database path
For 64-bit Windows, use HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\LonWorks\NSS\Configuration\EchelonSupport\Directory Name
Please be sure that you have full access and privileges on the database folder and its dependents. It might also help to start LonMaker as Administrator (right-click LonMaker.exe and select Run as Admin).