I just started seeing these a few days ago and I know for a fact there is a huge amount of disk space on the server hosting the MTA, so I am not sure why these messages are appearing:
<01/25/12 04:11:51> DIS: MSLOCAL: Less than 1 kBytes of disk space available
<01/25/12 04:51:51> DIS: MSLOCAL: More than 1 kBytes of disk space available
The messages have show up a handfull of times since 1/20. Could not find anything on other forums, or in the KB. Any ideas?

Thanks in advance!