Fritz,
I'm making an assumption that the version of Netsight you have installed is on a windows system. By default a windows install of Netsight includes a TFTPD, SNMPTrapD, Syslogd and a bootpd application.
A typical install will not only install all of these side apps, but also enable them.
Bootp port number is the same used for DHCP, so you are likely seeing local DHCP requests on the network (because they are broadcast) hit the bootpd process. We don't actually do anything with them....but they are listed in the syslog tab. Easiest way to correct this issue would be to disable the bootpd process on the Netsight server. (again assuming this is windows) If you are on the server itself, there is a services icon in the system tray. From there you can disable the bootpd process. This should help you determine if this is indeed your issue.
If this does correct the issue, I think you need to go into Netsight, tools, options, there should be a place to uncheck bootpd as normally it will start up every time you restart the server.
Chris
