Help- re-install of 5.1 release leaves bootloader unworkable

[Scott W]

Hey all- hopefully someone can point me in the right direction here.  
After problems with cvsuped 5.1 current, I did a re-install of 5.1 
RELEASE on a system with two IDE drives.  The install appears to go 
well, but on reboot, I'm faced with what appears to be 3(!!) options for 
booting BSD, none of which work.

The system is a dual celeron 366MHz with 768M RAM.
HPT66 IDE controller which has 2 IDE drives plugged into it.
These show up as ad4 and ad5 during the install.

The boot menu shows as:
F1 freebsd
F2 freebsd
F3 Disk 1

none of which work.
If I type:
unload
boot 3(ad1,d)
I get an error 1 lba 0

Other selections result in:
no /boot/loader

I have been able to load the fixit disk, and mount the correct 
partitions, but the only references I've seen to any help with respect 
to re-installing the boot loader are 'installbootloader' which doesn't 
appear to be on this install. 

So...how do I recover this install and remove the 'bad' entries in the 
loader, and point it at the correct disk?

Disk layout is as follows:
ad3s1a /tmp      2G
ad3s1b   swap   2G

ad4s1d /boot   128M
ad4s1a /            1G
ad4s1e /var         2G
ad4s2d /usr         10G
ad4s1b /home      5G

Scott