Excess flood means you sent too much data (messages) too fast...
If you haven't already enabled flood control, do it now
CTRL-O >> IRC -> Flood ---> enable the check boxes before Own messages
and Enable flood protection
. If that doesn't help, set Trigger flood check after:
to a lower number, like 200.
This will queue lines that are typed (or sent by a script) too quickly and wait a while before sending it. The bad part is that there can be some delay on messages your bot, but the good part is that your bot shouldn't be disconnected anymore for excess flood
You could also use /play for sending the bigger chunks of text, just put all text in a file and then /play -a cprivmsg $nick file.txt
/play will send all lines with a second pause between them, so there's less risk of being kicked off the server. Also see /help /play for more features and switches