Net Waiting

I have an XPS M140 with Net Waiting BVRP software, Version 2.5.23, installed by Dell.  Net Waiting suddenly started working about a year after I bought the computer, and just as suddenly stopped working a few months ago.  The Net Waiting symbol is on the toolbar, and it says it's working, but it doesn't activate when someone calls me while I am on the internet. And in my rural area we have only dial-up, and one telephone line.  What is going on and how do I reactivate Net Waiting?