I agree with dasgar - you are only doing one split! Either do it as dasgar suggests, or keep it simple and just use split:

  DB<5> $s = q/"foo:bar","test:boing!","whirrr:clunk"/;
  DB<6> %hsh = split /[:,]/, $s; ## do both the required splits in one
+ step
  DB<7> x %hsh

0  '"whirrr'
1  'clunk"'
2  '"foo'
3  'bar"'
4  '"test'
5  'boing!"'
[download]

Admittedly this test will be caught out by delimiters inside the quotes and spaces between the key/val pairs, but it is a start as to how this problem could be solved... TIMTOWTDI!