[Bioc-devel] Namespace and function 'open'

Hello,

 I built a package, everything was working very well. Now I included a
 NAMESPACE to export only some variables. (export(f, g, ...) )
 Everything is working fine, except one function. There I get an error:

 Fehler in UseMethod("open") : keine anwendbare Methode f?r "open"

 In this function I use the function "open" to generate an output bar.

  if (verbose) {
     pbt <- new("ProgressBarText", length(ids), barsteps = as.integer(20))
     open(pbt)
   }
     for (i in seq(along=ids)) {
       if (verbose) {
       update(pbt)
     }

 How I have to change my NAMESPACE file to fix this problem?