As you already have licenses, you can determine from that whether v4.1 (or other version) is sufficient for your situation or not, why would you need specifically v4.1, a version that's at least 3 years old(!), to determine whether you could use LLBLGen Pro or not?
Besides, I'm sorry but we don't give out trial licenses to old versions, only the latest version. There's no v4.1 trial installer available anymore.