unresolved symbol errors

[Max <davros@cyclone.Stanford.EDU>]

I'm trying to compile a program (Arla) that creates a module called
xfs.o.  When I try to load that module with insmod, I get the
following:

xfs.o: unresolved symbol mod_use_count_
xfs.o: unresolved symbol inode_setattr
xfs.o: unresolved symbol register_symtab_from
xfs.o: unresolved symbol current_set
xfs.o: unresolved symbol clear_inode
xfs.o: unresolved symbol kmalloc
xfs.o: unresolved symbol unregister_chrdev
xfs.o: unresolved symbol register_chrdev
xfs.o: unresolved symbol namei
xfs.o: unresolved symbol verify_area
xfs.o: unresolved symbol read_exec
xfs.o: unresolved symbol apic_reg
xfs.o: unresolved symbol sys_call_table
xfs.o: unresolved symbol __get_free_pages
xfs.o: unresolved symbol open_namei
xfs.o: unresolved symbol unregister_filesystem
xfs.o: unresolved symbol iput
xfs.o: unresolved symbol update_vm_cache
xfs.o: unresolved symbol lnamei
xfs.o: unresolved symbol generic_file_mmap
xfs.o: unresolved symbol panic
xfs.o: unresolved symbol down_failed
xfs.o: unresolved symbol generic_file_read
xfs.o: unresolved symbol __iget
xfs.o: unresolved symbol register_filesystem
xfs.o: unresolved symbol free_pages
xfs.o: unresolved symbol invalidate_inode_pages
xfs.o: unresolved symbol up_wakeup
xfs.o: unresolved symbol interruptible_sleep_on
xfs.o: unresolved symbol kfree
xfs.o: unresolved symbol wake_up
xfs.o: unresolved symbol printk

I'm running kernel 2.1.121 though the system was originally set up for
2.0.33.  Is there some library that I'm missing?  Everything compiles
fine, so I don't understand why I'm getting these errors.

Thanks for any help,
    Max