I tested several large data sets including a 6000 line ebook, a big HTML page, UUencoded test from an email and a large text report with no punctuation. All processed quickly, not able to trigger infinite loop behaviour.
As this bug is nearly 5 years old, it may well be related to the regular expression engine used in Perl at that time, and may no longer occur.
If you can provide specif data to reproduce this condition, I can look into it further.