R help - May 2011 - object not found with %dopar% when using foreach

Dear R-List member,

  tried implement the foreach loop. It works fine, when I'm using %do%, 
but not when I'm using %dopar%.
I always receive one of the following error messages:

error in { : task 1 failed - "Objekt 'S3' not found" - could
the
.export  be an solution for this??
Any help is much appreciated!

The Code hast the following structure:
##########
dft3 = function (...) {
     ...
}
optDFT = function (...)
     ...
     for (sit in 1:n.sit){
         S3 = ...
         pDFT3 = ... dft3(..)
     }
     return(LL.DFT)
}
foreach(k=1:n.run)  %dopar% {
         for (j in 1:n.subj) {
         ...
         valuesDFT = nlminb(start=..., objective = optDFT)
         }
}

-- 
____________


lic. phil. Nicolas A. J. Berkowitsch
Universit?t Basel
Fakult?t f?r Psychologie
Economic Psychology
Missionsstrasse 62a
CH-4055 Basel

Tel.     +41 61 267 05 75
E-Mail   nicolas.berkowitsch at unibas.ch
Web     
http://psycho.unibas.ch/abteilungen/abteilung-details/home/abteilung/economic-psychology/