R help - Jul 2013 - qtlnet mcmc.qtlnet sample genetic architeture and QTL network

Im working with the "qtlnet" package and want to sample the genetic
architecture and QTL network. I aiming to do this with the function
qtlnet:::mcmc.qtlnet. So far so good. However I cant do it with my own
cross dataset. data(Pscdbp) works fine, but not my own. I mean it is from
class "cross". However, I receive the error:

Error in dimnames(geno.dat)[[2]] <- tmp : 'dimnames' must be a list

Can anybody help me out? I uploaded my crossdata here:

http://www.risclab.com/cross_gpsm.RData

Would be awesome if somebody could help me out