You can't. The iPad does not support Flash. I'm not sure about Active X, but probably not.
There are a few Flash capable browsers for the iPad. They don't work very well, since they are essentially remote sessions on a server, but they may be good enough for your purposes. The most common mentioned are iSwifter, Skyfire, and Puffin.
The other option is to use a remote desktop client to control a desktop computer. Splashtop is popular and cheap.