I get the "internal error: lstream" message every time I try to
decode an image in Gnus. I am using 21.4.8 under SuSE 8.1, but a
WWW/News search reveals this is a long standing bug.
Nearly identical symptoms were reported ten months ago in 21.1.14, with
some analysis:
http://groups.google.com/groups?selm=mailman.1013561161.740.xemacs-news%4...
From the backtrace provided in the message linked to above, it seems
that the crash happens when the stream is tickled during a garbage
collection. This may be an important detail, or not.