I have gone through your symbol and i found that there is no "global signal name" property in your symbol.
You have to add this property in the symbol by using symbol editor.
For all the power supply symbols also you have to follow this one.
See the attachment for more details.
I hope this one will help you.
In the PADS flow Global Signal Name is replaced by NETNAME so the symbol would appear to be correct.
The symbol looks like it is correct, so can you show an example of how you are connecting these nets together? Is the net missing from symbols physically connected to nets that have the special symbol attached, or are you missing the connection on symbols that have 'implicit' ground pins, those with SIGNAL=GND properties?