Description of problem:
Browsing rpm archives now produces "unknown tag" error.

woring workaround:
comminting out these attributes in /usr/share/mc/extfs/rpm fixed it for me:

@@ -95,10 +95,10 @@ mcrpmfs_list ()
         echo "$FILEPREF 0 $DATE INFO/PACKAGER"
      test "`$RPM -qp --qf \"%{URL}\" \"$f\"`" = "(none)" ||
         echo "$FILEPREF 0 $DATE INFO/URL"
-     test "`$RPM -qp --qf \"%{SERIAL}\" \"$f\"`" = "(none)" ||
-        echo "$FILEPREF 0 $DATE INFO/SERIAL"
-     test "`$RPM -qp --qf \"%{COPYRIGHT}\" \"$f\"`" = "(none)" ||
-        echo "$FILEPREF 0 $DATE INFO/COPYRIGHT"
+##     test "`$RPM -qp --qf \"%{SERIAL}\" \"$f\"`" = "(none)" ||
+##      echo "$FILEPREF 0 $DATE INFO/SERIAL"
+##     test "`$RPM -qp --qf \"%{COPYRIGHT}\" \"$f\"`" = "(none)" ||
+##      echo "$FILEPREF 0 $DATE INFO/COPYRIGHT"
      test "`$RPM -qp --qf \"%{EPOCH}\" \"$f\"`" = "(none)" ||
         echo "$FILEPREF 0 $DATE INFO/EPOCH"
      test "`$RPM -qp --qf \"%{LICENSE}\" \"$f\"`" = "(none)" ||

Problem is with SERIAL and COPYRIGHT attributes...

# rpm -qp --qf %{SERIAL} *rpm
error: incorrect format: unknown tag

(maybe problem of rpm base package?)