$var =~ /(["'])[^(??{"$1"})]*?\1/; which worked unless $1 contained a 
+special character (forgot the character, but it wasn't a quote),
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I don't quite understand this? How could $1 contain anything other than ["']?

I guess $1 had to be a quote, but in the error message, $1 was replaced with the string of matched characters, which were all non-quotes since I negated $1 in the regex. I don't recall the entire [^(??{"$1"})] being replaced, which makes it seem like the string of non-quotes in the error message was made of characters from only $1.

Anyway, it appears as though the characters matching ^$1 in my regex were interpolated, causing errors, and quoting them in the regex would have quoted the square brackets, the ^, the (??{", etc. and prevented the very character that I really wanted to quote from being matched.

My simple .*? between the quotes works for me, and my other idea is overkill for my current project anyway. I'll analyze the solutions from this thread when I have a chance. I'm sure they solve the problem.