To long domain name?

[Administrator www.pes.cz - nejlepsi pritel kazdeho webmastera]

Hello,
I have one problem.
I cannot run domain   which is 91 character long.
My DNS server run on BIND8 ( i try it also on BIND 9) and when I want to
reload configuration,
I have this message in log file:

Can't make zone  'mydomain' : canonical.

I haven't any other "." in the name only: domain.cz.

Can anybody help me?

Thanks

Milan