BUG #5041: Changing data_directory problem

The following bug has been logged online:

Bug reference:      5041
Logged by:          Jonas
Email address:      jonasdonovan@hotmail.com
PostgreSQL version: 8.4
Operating system:   Ubuntu 9.10
Description:        Changing data_directory problem
Details:

After changing data_directory - in the same way as I did for postgres 8.3 -
postgres 8.4 gives me:

root@ip-10-224-94-129:/mnt/postgresql/8.4/main# sudo
/etc/init.d/postgresql-8.4 start
 * Starting PostgreSQL 8.4 database server
Error: could not exec /usr/lib/postgresql/8.4/bin/pg_ctl
/usr/lib/postgresql/8.4/bin/pg_ctl start -D /mnt/postgresql/8.4
/main -l /var/log/postgresql/postgresql-8.4-main.log -s -o  -c
config_file="/etc/postgresql/8.4/main/postgresql.conf" :