The following code works under my environment. Test it under your environment and maybe it'll jog your brain a little to help you figure out your problem...
Sorry it took me a while to get back to you.
cd c:\temp
create database tester
create table testertable (iid i(4), cfirstname c(25), clastname c(25))
create sql view lv_testertable as select * from testertable
* At this point go into the database container
* and make the view updateable
use lv_testertable nodata
insert into lv_testertable (iid, cfirstname, clastname);
values(1, "My First Name", "My Last Name")
=tableupdate()