PAM authentication problem

I am having a problem with my Solaris 8 box, which seems related to PAM, 
but it somewhat peculiar/troubling.  I am able to login to the box via 
telnet without a problem, but when I try to su to root, I get the 
following:

Mar 19 11:01:40 boromir su: [ID 308033 auth.debug] pam_acct_mgmt: error Get 
new authentication token
Mar 19 11:01:40 boromir su: [ID 810491 auth.crit] 'su root' failed for root 
on /dev/pts/2

When I try to su to root with the incorrect password, I get:

Mar 19 11:01:47 boromir su: [ID 427203 auth.debug] pam_authenticate: error 
Authentication failed
Mar 19 11:01:47 boromir su: [ID 810491 auth.crit] 'su root' failed for 
fmonkey on /dev/pts/2

Notice that in the first one, I get "su root failed for *root*", but in the 
second it fails for my username.  Perhaps this is a resource problem (i.e., 
file handles, etc.)?  Does anyone have any ideas?

ahp