Some time ago, I've got a similar error message (I think, it was with perl5.6): IIRC the Problem was $anything =~ /$string/;

Since my strings were not unicode string, I was able to solve it by quoting the string, e.g. $anything =~ /\Q$string\E/;

But I don't know if you have really got the same problem as me.

Best regards,
perl -e "s>>*F>e=>y)\*martinF)stronat)=>print,print v8.8.8.32.11.32"