As the author of Schedule::Cron::Nofork, I can tell you how I circumvent the problem of long running tasks - I do the detachment within the started program, by using the start command of the Windows shell instead of relying on the buggy fork() implementation of Win32 Perl, which I experienced to have problems over the long term. After 3 or four days of spawning something every ten minutes, the main thread would just sit there.

Other than that, Schedule::Cron::Nofork is the same as Schedule::Cron, so it won't be a solution for your problem I think.