[R] Probit function

[Noah Silverman]

Hello,

I want to start testing using the MNP probit function in stead of the 
lrm function in my current experiment.

I have one dependant label and two independent varaibles.

The lrm is simple

model <- lrm(label ~ val1 + val2)

I tried the same thing with the mnp function and got an error that I 
don't understand

model <- mnp(label ~ val1 + val2)

I get back an immediate error that tells me, "The number of alternatives 
should be at least 3"

Since I have a binary training label, this looks like a problem.  
(Additionally, I thought that a probit was a appropriate tool for 
building binary models.)

Any advice?

Thanks!

-N