Problem opening KMM file

[Jack]

It looks like a circular process for now.  Try to open the file in the 
new version and grep to find the transaction that refers to the 
"missing" account.  In the working version of KMM, edit that 
transactions (you can do Ctl-Alt-F and type in the transaction id to 
find it) and check that the Category refers to a valid (still existing) 
one.  Then save the file again and try to open it int he new version to 
find the next problem transaction.