If using http://localhost/arcgis/webadaptor try the FQDN instead. For example: http://bubba.bubba.com/arcgis/webadaptor
There are different ways, try netstat -an | find "6080" or telnet
telnet [domainname or ip] [port]
You didn't say if using SSL. IF so, look at that article I sent.
Also there are issues after upgrading to SP1
Try the following:
Stop ArcGIS Server service
Go to C:\Program Files\ArcGIS\Server\framework\etc\upgrade.txt
Delete this file (upgrade.txt) if it exists.
Start ArcGIS Server service
For the "Could not find any recognizable digits." error what has worked for me before is a repair of web adaptor. go to control panel, programs, uninstall, uninstall web adaptor SP1, then choose Repair option. If that doesn't help, try an uninstall. Check that the arcgis (or whatever folder you called it) is removed, if not, delete, then re-install SP1 for Web Adaptor
Using SSL? If not using SSL, go to IIS Manager, click Default Web Site, under Actions, click Bindings. If https on port 443 is present, remove it.
Also check that the IIS Admin Service is started Are you able to get to the web adaptor configuration page at all?
If so, select " Enable administrative access to your site through the Web Adaptor"