Proportional Odds

Dear All, I have been coding a Proportional Odds Emax model for some categorical PD data. The model seems to be sensitive to initial estimates of the baseline odds. The SE in the final estimates after a few trials comes to be 30% at worst. Any suggestions on methods to make better guesses for initial values of baseline odds from the given data? Another question would be - is it possible to generate confidence bounds on probabilities using NONMEM for such a model? Thanks, Sathej