The "perl" output module in smidump seems to be a little naive about backslashes. (Given the output language, I can understand a little difficulty in getting all the special characters escaped correctly.) Rather than trust the offending string to a mailer, I've included it as an attachment. It's taken from CISCO-SLB-EXT-MIB.my, which is part of the CISCO MIB collection. The perl output won't compile, and the problem seems to be that '' gets rendered as '\' (the backslash in the middle isn't being doubled).
This problem was found with version 0.4.3, running on Linux/x86.
[I may wind up fixing this one myself while fixing another problem. Look for a post about the joys :-) of HP-UX in a few days.]
SlbRegularExpression ::= TEXTUAL-CONVENTION DISPLAY-HINT "255a" STATUS current DESCRIPTION "A regular expression of length 0 to 255. Regular expressions are typically used for matching fields in Layer 7 data streams, such as URLs or Cookies in HTTP. The following syntax is based on the file name matching algorithm commonly employed in UNIX : '*' matches zero or more characters; '?' matches exactly one character; '' means escaped character, e.g., '*' matches the character '*'; a bracketed range matches any single character from the range, e.g. [0-9] matches '0', '2', and '9', but not 'a'; a leading ^ in a range means don't match any in the range; '+' matches any sequence of one or more characters; '.' matches any single character; All other characters represent themselves. '\a' matches alert (ASCII 7); '\b' matches backspace (ASCII 8); '\f' matches form-feed (ASCII 12); '\n' matches newline (ASCII 10); '\r' matches carriage return (ASCII 13); '\t' matches tab (ASCII 9); '\v' matches vertical tab (ASCII 11); '\0' matches null (ASCII 0); '\' matches backslash; '\x##' matches the ASCII character whose hexadecimal representation is ##. " SYNTAX OCTET STRING (SIZE (0..255))