The 6th line of DH.pm has use Math::BigInt lib => "GMP,Pari";

That means it will try to use Math::BigInt::GMP. If that fails it will try to use Math::BigInt::Pari. If that also fails it will use Math::BigInt::FastCalc and print out the message.

I would be surprised if installing Math::BigInt::GMP would fix the segfault. I would think the segfault is being caused by a different issue - but I don't know what that issue is.

I think that In perl5.6.0 , doesn't has GMP and Pari files.

Without GMP and Pari, I don't think you would have been able to get Net::SSH::Perl to install - but I've never used Net::SSH::Perl, and am no expert.
Instead, I use Net::SSH2 - which needs the libssh2 library.
I *think* Net::SFTP also provides good mileage on linux - though I've never used it either, as I'm on Windows.

Cheers,
Rob