Bot causing "Headers already sent" errors

[DavidCT]

Running 1.1.13, modified a bit

Never had any Cannot modify header information - headers already sent errors in my logs, until yesterday through today when a bot from 199.15.234.78 (listed as owned by a server company) visited.  Many errors, every page hit, but only from this IP, no other user - ever.  Also had session_start() [<a href='function.session-start'>function.session-start</a>]: Cannot send session cache limiter - headers already sent and session_start() [<a href='function.session-start'>function.session-start</a>]: Cannot send session cookie - headers already sent errors by this IP, unsure why the HREF thing.  Anyone know what is going on here?  I blocked the IP range in htaccess, but I wonder why it happened.  Thanks.

[Aleksi "Lex" Kilpinen]

Can't think of any exact reason to this, if no one else has ever caused such errors...

[DavidCT]

...and nobody has since.  I just figured I'd ask in case I had fouled up something.  Thanks.