Code:
if (Create == $$1) && ($$2 != $null) && ($$3 != $null) && ($$4 != $null)


can be shortened to

Code:
if (Create == $1) && ($4)


(if $4 exists, then so do $2 and $3 !)
Also -- why the notices on three lines and not just on one?

To add to the hashtable, use

Code:
hadd tablename $2 $3 $4


Also, the alias loadhost you might wanna check if the table exists before creating it, or destroy it before creating it. Attempting to create a table that already exists causes an error.