Why I can NOT use Free Phone on DSL line??? (dialpad, and more)

[gredodenda]

I'm now using DSL at my home and when I go to internet for free phone like Dialpad, Phone Hog, PhoneFree.com and FreeWebCall.com, NONE of them allows to make a call.
Why is that?? How do I make this work? Is it DSL? Does DSL can't make a internet call??
Anyone using DSL line, can you make a call???
Please help me, free phone call to international was one of my reason to subscribe DSL and now it doesn't work. Need HELP!!!

Thanks

 

[HappyFace]

III. Yes
2. Cheese is good
C. Blue
10. Plastic Turtle

Hope this helps!!

 

[NikPreviousAcct]

it might be because DialPad (or whatever) gets information from your ISP as to where you're calling from -where you're dialing in from.

maybe?