SQL Service Pack 6a not working on Proli

I am installing Microsoft SQL Server 6.5 on a compaq proliant 1850r, using a Compaq Smart Array 221 controller. Service pack 3 and 4 for SQL will install fine, but if I try to install service pack 5 or 5a for SQL the installation dies trying to update the catallog with the error message “Setup inillation could not be excuted. CFGCHAR.EXE could not be excetued”. Does anyone have any ideas what could be wrong.