[Samba] smbcquotas tells me that "quotas are not enabled"

[Luke Hamilton]

I have a setup of Ubuntu 8.04 running Samba 3.0.28a.  Connected to our network I 
have a buffalo linkstation acting as Network Attached Storage (NAS), which I 
have successfully mounted on the local file system.

Using smbcquotas I believe I can set up a quota for each user on the NAS.  To 
get started, I run the command:
smbcquotas //192.168.1.4/share -S FSQFLAGS:QUOTA_ENABLED -A /etc/.credentials

But I get the error:
Quotas are not enabled on this share.
Failed to open \$Extend\$Quota:$Q:$INDEX_ALLOCATION  NT_STATUS_ACCESS_DENIED.

I'm trying to figure out why my command fails.  Shouldn't that enable quotas in 
the first place?