IMAP LIST failing.

[mail132:...sbin] root[282]# ./imsimta version
Sun Java(tm) System Messaging Server 6.2-8.01 (built Nov 27 2006)
libimta.so 6.2-8.01 (built 16:38:47, Nov 27 2006)
SunOS mail132 5.10 Generic_118833-36 sun4v sparc SUNW,Sun-Fire-T200

I'm running into a issue where the LIST "" "*" command is failing to  
list the folders for a user. It's happening when one of our mailmove  
processes is logging in as the store admin user, proxyauth'ing to the  
user and then issuing the list command. No mailboxes will be  
returned. However, if I telnet to the IMAP port and issue the same  
sequence of commands, the list will work.

Here are the telemetry logs showing what I'm talking about:

[mail132:...m_rogers1] root[289]# more 1192043535
LOGIN m_rogers1 2007/10/10 12:12:15
>0.001>. OK Completed
<0.055<. LIST "" "*"
>0.000>. OK Completed
<0.000<. LOGOUT
>0.000>* BYE LOGOUT received
. OK Completed
LOGOUT m_rogers1 2007/10/10 12:12:15 - 2007/10/10 12:12:15

[mail132:...m_rogers1] root[290]# more 1192043718
LOGIN m_rogers1 2007/10/10 12:15:18
>0.001>a OK Completed
<3.735<a list "" *
>0.001>* LIST (\NoInferiors) "/" INBOX
* LIST (\HasNoChildren) "/" "Deleted Messages"
* LIST (\HasNoChildren) "/" Drafts
* LIST (\HasNoChildren) "/" "Sent Messages"
a OK Completed
<4.562<a logout
>0.000>* BYE LOGOUT received
a OK Completed
LOGOUT m_rogers1 2007/10/10 12:15:18 - 2007/10/10 12:15:26

It's also not specific to the user. Here are the telemetry logs from  
another user:

[mail132:...spice_h] root[293]# more 1192045021
LOGIN spice_h 2007/10/10 12:37:01
>0.000>. OK Completed
<0.063<. LIST "" "*"
>0.000>. OK Completed
<0.000<. LOGOUT
>0.000>* BYE LOGOUT received
. OK Completed
LOGOUT spice_h 2007/10/10 12:37:01 - 2007/10/10 12:37:01


[mail132:...spice_h] root[294]# more 1192045062
LOGIN spice_h 2007/10/10 12:37:42
>0.001>a OK Completed
<3.891<a list "" "*"
>0.001>* LIST (\NoInferiors) "/" INBOX
* LIST (\HasNoChildren) "/" &Tgtm+DBN-
* LIST (\HasNoChildren) "/" &UkqWZDBXMF8w4TDDMLsw,DC3MJk-
* LIST (\HasNoChildren) "/" &UkqWZDBXMF8w4TDDMLsw,DC4-
* LIST (\HasNoChildren) "/" &kAFP4W4IMH8w4TDDMLsw,DC4-
a OK Completed
<2.883<a logout
>0.000>* BYE LOGOUT received
a OK Completed
LOGOUT spice_h 2007/10/10 12:37:42 - 2007/10/10 12:37:49

Any ideas?