thanks to everyone for the help. One way I managed to get pass this error was to edit the mxsplpal.2da and mxsplran.2da files and reduce the level from 50 to 40. I then installed BP and level-50 ruleset installed with no problems.
Once the BP install completed, I checked the above 2 files and they were definitely corrupted. 2 additional 5 and 6 columns had been added with incomplete number of rows. I used
DLtCEP to fix the files by removing the additional columns and saved the corrected files in the override directory.
I did a quick check with CLUA for both the Paladin and Ranger and both were able to reach level 50 with no major issues (i.e. the game did not crash).
Thanks again.