Based on the screenshot you still have the mini version installed. Mini is not a compatible version. You need to have a standard or mega version of dd-wrt installed.

So in case of WRT54GL you can go with:

Build 13064 Standard Generic and use the setup command method to set it up OR

Build 14896 Standard Generic and use the built-in Hotspot System part

For problem #2: this can be a browser issue, try it with Internet Explorer.