There is no hot backup agent if you are asking whether or not there is direct support for hot backups or "online" backups. However like most databases, you can do it by having DB2 do an online backup to disk first, then the regular arcserv client (or any client for any backup product for that matter) can come along and simply back up those files and even erase them afterwards.
Unfortunetly this implies you have that amount of spare disk space sitting there for that purpose. For smaller databases (since you asked regarding windows i assume this is the case) this is actually cheaper then buying an agent. An agent really only makes sense for larger databses when the cost of the agent is cheaper then the disk space to do the above technique.