FWIW, I encountered the same problem when I installed Math::BigInt::GMP improperly. I tried to install it without having libgmp3 installed. When it failed (unable to find gmp.h) I installed the library, then did another 'make' and 'make install'. It broke (unknown symbol) until I went back, did 'perl Makefile.PL' to remake the makefile, then reinstalled (this time, with 'make test' first, like I should have done the first time). Without Math::BigInt::GMP, Net::SSH::Perl was really slow, taking over a minute to connect. Net::SFTP::Foreign supports password authentication now, with the latest versions (albeit as an experimental feature). That's probably the only reason I didn't use it before.