Invalid conference room

Hi all,
I have installed asterisk-1.2.13 and zaptel-1.2.13 in Fedora Core 6. The conferencing feature is used without any hardware. After successfully installing zaptel, changed the kernel version to 2,6,18 in usr/src/zaptel/xpp/xbuscore.c and removed the # before ztdummy in zaptel makefile. Now when i use the meetme command to use conferencing feature. I get the message as there is no invalid conference and getting the error "unable to dup channel : no such file or directory.

Kindly tell me how to overcome this problem.

Thanks in advance.