if statement at form 'on load' using lookup dropdown as criteria

if statement at form 'on load' using lookup dropdown as criteria

cant seem to get this to work....please help

if(TZ2WOF_PEs.!= "-Select-")
{
TZ2WOF_Select.deselect();
show TZ2WOF_PEs;
TZ2WOF_Select.select.("PEs");
}

fyi
TZ2WOF_PEs is lookup field in dropdown mode
TZ2WOF_Select is a checkbox

Thanks in Advance