problem in running plpgsql functions

hi,   I'm a new plpgsql user trying to  learn , how to write functions
using PL/pgSQL. Unfortunately when I try to run the functions (even
straight copies from the manual) I get one of the following errors :
-    cache lookup for language %d failed 139330
-    stat failed on file /usr/local/pgsql/lib/plpgsql.so
Unix command "stat" executed manually for the file
/usr/local/pgsql/lib/plpgsql.so runs "successfully".
Under the regression tests it is indicated that both plpgsql & pltcl
are  "OK".
I think that there is a problem trying to load plpgsql.so dynamically
into the backend        ( how come the regression tests for plpgsql and
pltcl are running well????) .
I am using a cyrix MII 300 mhz CPU with 32 mb RAM running RedHat Linux
ver. 5.2 with kernel 2.2.4. The following are installed : postgreSQL
version 6.4 , libc-5.3.12-28 / ld.so-1.9.5-8 / libelf 0.6.4-2 /
aout-libs 1.4-9.
I havent been able to figure out the problem exactly.........and any
advice on how to get the functions running will be very welcome.
Waiting eagerly for an early reply from one of you brainy people out
there......
Thanx.
Vinnie .
vinniesingh@netscape.net
vinnie_singh@hotmail.com
vwsingh@ch1.dot.net.in