Stephanie,
please do some monitoring of your server as in this article:
http://msdn2.microsoft.com/en-us/library/ms176018.aspx. It'll give some more
info about what is happening over time.
Also check out how much memory is in your server, and what other processes
are running (eg is it also an exchange server or webserver)?
Cheers,
Paul Ibison SQL Server MVP, www.replicationanswers.com .

When I issue the command, sp_browsereplcmds, it returns

Msg 6513, Level 16, State 27, Procedure sp_browsereplcmds, Line 110
Failed to initialize the Common Language Runtime (CLR) v2.0.50727 due to
memory pressure. Please restart SQL server in Address Windowing Extensions
(AWE) mode to use CLR integration features.