help with IRIX 3.3.1 update!!

[zyda res acct]

Hi,
yesterday I installed IRIX 3.3 on my 4D/25TG using autoinst. When I
loaded the 3.3.1 maintenance release I received the following error
message:

>Pre-Installation check failure:
>The following subsystems cannot be installed beacause they are
>replaced by newer versions already on the disk. If you want to
>install the older versions, you must remove newer versions first.
>
>	maint1.dev_man.cc		C compiler and support
>	maint1.dev_sw.cc
>	maint1.dev_sw.crypt		Security Admin Lib
>	maint1.dev_sw.sccs		SCCS utilities
>	maint1.nfs_man.nfs		NFS support
>	maint1.nfs_sw.dskless	Diskless support
>	maint1.nfs_sw.nfs		NFS support
>	maint1.nfs_sw.yp		Yellow pages

I am not a systems admin type and would like to know if anyone has
run into this problem. Why would the 3.3.1 maintenance update tape
contain older versions of software that has been previously installed?
Am I missing the boat here?

thanks,
george dabrowski