Hi Same,
firstly you have two errors you need to fix. The first Erik mentions above. The second is that you have a corrupt version of Navision Client installed. This could have happened for a number of reasons, most likely being either you applied hotfix incorrectly, or maybe you have incorrectly installed a different language. Becasue basically the version of the STX file you have is not the same as the Fin.exe file. Also make sure you have a good version of 4.00sp3, I recommend build 26565.
Also the move to 64bit is a good one, but do you have a good reason for using clusters? It may just plug and play, but also you may have a lot of problems getting Navision to work with a cluster. Log shipping and othe such disaster recovery methods generally are better options for Navision. Unless of course you can not even afford a few minutes of downtime.