We've had issues with wireless getting bogged down before with netbook carts and have implemented a couple tweaks to alleviate the congestion a little.
1) If your wireless system is centrally managed, then disable the slower data rates. If all your devices are 802.11G or better, then flat out disable all the 802.11B data rates. You would be surprised how much faster this can make wireless when using entire cart of 30 netbooks for web browsing.
2) Enable "Always wait for the network at computer startup and logon" in GPO. It'll take a few more seconds to get to a logon prompt, but the system will wait for the wireless connection to associate instead of using cached credentials. This setting can be found in Computer Configuration\Administrative Templates\System/ Logon.
3) Tighten up the code in the VBS script as much as possible. The less code the client has to crunch the better. I would start by doing away with the separate if/end if statements for all the different computer names and go with If/ElseIF statements.