Yeah, if the Wireless Access Point has an issue with DNS it can come and go, and that would explain why it works fine wired but not wireless. Without knowing a LOT more about the network structure there I can't say much more for sure.

Yeah now I am at work and it works fine. Should I still try what you told me to do?

Nope. Rule 1 of troubleshooting is don't fix it when it's working. If you change something now you won't know if it's worked and you'll be wondering about it for weeks and weeks.