Backend cache problem revisited

Hi,

after reading through the archives it seems that this particular error

        NOTICE:  SIAssignBackendId: discarding tag 2147483553
        Connection to database failed
        FATAL 1:  Backend cache invalidation initialization failed

had not come up for a while for most people.  However I didn't see any
postings about a solution either, so I tried to figure out if this
problem went away after the 6.3.2 build.  On 6.3.2 this error occurs
after there are more than 32 concurrent connections.  On 6.4.2 the
number of concurrent connections allowed doubled to 64, but it occurs
again if you create more.  My system environment has dual PII450, 1GB
RAM, and I am running RedHat5.2 with Apache1.3.6 & mod_perl &
Postgresql6.3.2 (all RedHat builds except for the kernel).  I use
mod_perl to keep the database connection persistent. With 1GB of ram I
can hold at least 100 connections open at the same time, and I would
really like to be able to utilize my computer's resources fully.

Can anyone tell me how to reconfigure postgresql so I can avoid this
error when opening more connections?  Any help is greatly appreciated.

Regards,

Yin-So Chen