Ok, lets start from the beginning, as it seems the most of the work is already done.
Using the configuration you provided, can you ping the other end of the same subnet in the opposite equipment?
(before trying anything, please confirm that all (sub)interfaces are UP)
On the switch, subnet 1 IF, ping the IP address of netscreen subnet 1. If it succeeds, please do the opposite. (Netscreen -> Cisco)
Repeat on all subnets.
Regarding routing, I think it wouldn't be possible to make Netscreen route traffic between VLANs. I don't have personal knowledge with Netscreen 25 device, but I think it isn't possible to achieve the "router on a stick" scenario with this equipment.
After looking over you basic config , you mention you set port fa0/24 to trunk, but have you added the native / allowed VLANs to that trunk?
the commands would look something like this:
<b>Switch(config-if)#switchport mode trunk
Switch(config-if)#switchport trunk native vlan 1
Switch(config-if)#switchport trunk allowed vlans all</b> (or <b>allowed vlans add 2-3</b>)
let us know how things turn out...