SYSCTL Functions

[pradeep]

HI,
this is pradeep and i am naive user of FreeBSD.
I am using FreeBSD 6.2 , writing a device driver module in which
i want to access variables in run time as a debugging information resembling
/proc file system in linux.  I thought of using sysctl functions but 
when i load the
module i m getting the following error
link_elf_obj: sysctl__cvmx_children symbol undefined
kldload: unsupported file system.

The code i wrote looks like this:
SYSCTL_DECL(_cvmx);
int dev_id;
STSCTL_INT(_CVMX, 2, dev_id,CTLFLAG_RW,&dev_id,0,"device number");

Can anybody help me regarding
sorry for my language.

Thanks in advance,
pradeep