Can't access my PC remotely.

Got a bit of a problem on my hands here.
I have few resources which i would like to access from externally. Some being Logmein.com, Serv-U FTP access, and UltraVNC and UltraVNC SC.

None of these work when trying to access from external sites such as my workplace. All relevant ports have been opened. 5500 for UltraVNC SC, 5800 and 5900 for UltraVNC for accessing though viewer or HTTP etc etc.

They all work when i try from my OWN Pc. I am behind a router and have a local IP address, and also use dyndns.org to forward my IP so i can use a single name.

Now i got a friend to try running the .exe which initiates the connection between mines and his PC so i can share his desktop allowing me to control his mouse etc (Ultra VNC SC). Nothing happened. I closed down Kaspersky Interent Security (in which I have allowed access for UltraVNC) and it did get a little further. Small pop-up appeared on my screen if i wanted to accept the incoming connection from my friend. I accepted and the screen sharing interface appeared but it was blank and the hour glass appeared and was able to do nothing apart from having to close it down.

It was a little progress but it does tell me that it was Kaspersky that was the problem. Another example being that i gave my friend my ftp address, nothing happened. Wehn i closed down Kaspersky, he was asked for username and password but he said that it was saying access denied.

I have allowed access for all these programs in Kaspersky but maybe im not doing it properly. I defintely know that im doing it properly on my own router. Is there any stickys or tutorials available that show me how to properly configure Kaspersky or does anyone else know what the problem could be (if you're awake after reading this!!).

Thanks

Yup both have public IP addresses.