in reply to DBD::Informix ld.so.1 unable to find .so file

First does 
ldd /apps/exlink/orc/arch/sparc-sun-solaris/perl/lib/site_perl
+/5.8.5/sun4-solaris/auto/DBD/Informix/Informix.so

[download]
find the library.

Try using the whole path rather than relative.

Ensure that everything is the same "type". Ensure that perl, module and library are all 32 or 64 bit

In Section Seekers of Perl Wisdom