R help - Feb 2012 - kernlab - rvm error message: Error in if (length(data) != vl)

Hi,

I am trying to perform relevance vector machines with the rvm-function from
kernlab.

On one dataset I get this message:

Setting default kernel parameters  

Error in if (length(data) != vl) { : 
RMate stopped at line 0 of selection
  missing value where TRUE/FALSE needed
Calls: rvm ... .local -> backsolve -> as.matrix -> chol -> diag
-> array


can someone explain this error message?

It works for other data-sets with the same feature / example-space.
But for one particular trainingset I get this error message...

thanks!