I'm pleased that you find this old application useful; though, you may find my more recently developed Batch Attribute Editor application a more powerful attribute editing utility, given that it offers the ability to edit attribute values across multiple blocks of varying block names.
You may argue that the use of a Script file to perform the attribute modification across multiple drawings is inherently less powerful than the ObjectDBX interface leveraged by this older program, however, ObjectDBX has too many bugs where attribute modification is concerned and so I have since abandoned it's use for this purpose.
Nevertheless, to allow the user to specify tags containing slashes (and other such characters), change the following lines:
Line 1265 from:
( (or (not (snvalid str)) (vl-string-position 32 str))
To:
( (vl-string-position 32 str)
Line 1457 from:
( (or (not (snvalid str)) (vl-string-position 32 str))
To:
( (vl-string-position 32 str)
Line 1579 from:
( (or (not (snvalid new_tag)) (vl-string-position 32 new_tag))
To:
( (vl-string-position 32 new_tag)
Line 2485 from:
( (or (not (snvalid tag_str)) (vl-string-position 32 tag_str))
To:
( (vl-string-position 32 tag_str)