[DVIPDFMx] pdf:fstream not working

[Alexander Grahn]

Hello,

I'd like to use the pdf:fstream special of dvipdfmx (version
dvipdfmx-20100328), but I can't get it working. I always get the error

  [1
  ** WARNING ** Could not open file: somefile.txt
  ** WARNING ** Interpreting special command fstream (pdf:) failed.
  ** WARNING ** >> at page="1" position="(112.681, 759.927)" (in PDF)
  ** WARNING ** >> xxx "pdf:fstream @obj1 (somefile.txt)"
  ]
  1779 bytes written

  ** WARNING ** 1 memory objects still allocated

when I try to process the dvi file generated from the minimal TeX file

  text
  \special{pdf:fstream @obj1 (somefile.txt)}
  \bye

The non-empty file `somefile.txt' resides in the same directory as the TeX
file and isn't opened by any another process. I am working under Linux.
Is there something wrong with my pdf:fstream usage?

Alexander