使用Net:SSH:Perl模块报错

今天机器上装的Net:SSHerl，运行后提示
Key class 'Net::SSH:erl::Key:SA' is unsupported: Math::BigInt version 1.78 required--this is only version 1.77 at /usr/lib/perl5/site_perl/5.8.8/Crypt/DSA/KeyChain.pm line 4, <GEN0> line 1.
BEGIN failed--compilation aborted at /usr/lib/perl5/site_perl/5.8.8/Crypt/DSA/KeyChain.pm line 4, <GEN0> line 1.
Compilation failed in require at /usr/lib/perl5/site_perl/5.8.8/Crypt/DSA.pm line 7, <GEN0> line 1.
BEGIN failed--compilation aborted at /usr/lib/perl5/site_perl/5.8.8/Crypt/DSA.pm line 7, <GEN0> line 1.
Compilation failed in require at /usr/lib/perl5/site_perl/5.8.8/Net/SSH/Perl/Key/DSA.pm line 14, <GEN0> line 1.
BEGIN failed--compilation aborted at /usr/lib/perl5/site_perl/5.8.8/Net/SSH/Perl/Key/DSA.pm line 14, <GEN0> line 1.
Compilation failed in require at (eval 23) line 1, <GEN0> line 1.
BEGIN failed--compilation aborted at (eval 23) line 1, <GEN0> line 1.
这个Math::BigInt模块已经从cpan上安装，为什么提示版本有问题呢

Math::BigInt version 1.78 required--this is only version 1.77