from the documentation for read.

   Note the *characters*: depending on the status of the
   filehandle, either (8-bit) bytes or characters are read. By
   default all filehandles operate on bytes, but for example if the
   filehandle has been opened with the ":utf8" I/O layer (see
   "open", and the "open" pragma, open), the I/O will operate on
   UTF-8 encoded Unicode characters, not bytes. Similarly for the
   ":encoding" pragma: in that case pretty much any characters can
   be read.
[download]

Sounds like your problem to me.