R help - Feb 2012 - solnp inversed-Hessian problem

Dear all,

I am tryng to solve a nonlinear optimization probel using the solnp function.
I have different datasets. For the smaller I get full solutions, for  
the bigger I got an error message stating:

########################################
Iter: 1 fn: 101.8017     Pars:  0.21000 0.21000 0.21000 0.21000  
0.21000 0.21000 0.21000 0.21000 0.21000 0.21000 0.21000 0.21000  
0.21000 0.21000 0.21000 0.21000 0.21000 0.21000 0.21000 0.21000  
0.21000 0.21000 0.21000 0.21000 0.21000 0.21000 0.21000 0.21000  
0.21000 0.21000 0.21000 0.21000 0.21000 0.21000 0.21000 0.21000  
0.21000 0.21000 0.21000 0.21000 0.21000 0.21000 0.21000 0.21000  
0.21000 0.21000 0.21000 0.21000 0.21000 0.21000 0.21000 0.21000  
0.21000 0.21000 0.21000 0.21000 0.21000 0.21000 0.21000 0.21000  
0.21000 0.21000 0.21000 0.21000

solnp--> Solution not reliable....Problem Inverting Hessian.
Warning messages:
1: In p0 * vscale[(neq + 2):(nc + np + 1)] :
   longer object length is not a multiple of shorter object length
2: In cbind(temp, funv) :
   number of rows of result is not a multiple of vector length (arg 1)
########################################


Anyone knows what may be the reason? Just remembering that the same  
problem runs OK for smaller datasets.

Thanks in advance,

Diogo Andr?
Portugal