Try this:

use lib '/home/neteng';
# use RRDs; # do this, or the eval statement (to check success/fail)

eval "require RRDs";
if( $@ ){ print "RRDs is not installed\n"; }
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See also use and perlfaq8 (What's the difference between require and use? How do I keep my own module/library directory? How do I add the directory my program lives in to the module/library search path? How do I add a directory to my include path at runtime? ).

HTH

Update: For what it's worth, the module couldn't be found because (as you point out) it wasn't in @INC. First add the directory for the module to @INC with use lib, then use or require it (don't include the '.pm' when using or requiring a module, and don't include the module name in a use lib statement). Oh, and use warnings; use strict;.