I am running a scan to a computer in internet and show me a looooooot of ports, and I know that it is not normall and that the all ports they are not open, I checked google but I could not find anything, somebody mention that probably is the firewall:

nmap -sS -sV -PO 192.168.1.1

Shows a lot of ports unknown and tcpwarpped, just want to see the open ports not the all the existing ports list.

But if I run the same command in a local computer shows me the really open ports.

What is worng? is it my firewall or I am mising another parameter?

It could be a defensive mechanism on the other side as well.   I have a firewall I put together a while back that responded OPEN on the first 1024 ports when scanned.   It was an IpCop Distro with a few add-ons.

Your command and parameter is ok. But dont use just one technique when scanning. That the beauty of nmap and its the most customizable scanner availble.  When you start combining timing options,etc... you sometimes obtain more reliable output. 

And don't forget the swiss army knife, netcat. You can always try connectign to the suspected port with nc -v 192.168.1.1 x where x is the port you want to connect to. If its open, you'll know along with its banner. Good luck.

I am using nmap with BackTrack 4 Beta, I am just experimenting a little bit, just to be familiar with it.

I tested from my office and showed me just the open ports, so I tested from my home again and I got all the ports open, so I decided to upgrade therouter's firmware for the Linksys WTR54GS and after that I can not ping outside, jajajajajaj, it was to late so I couldn't complete a test with the nmap, because told me to use the -PN switch.

Now, I have to figure out why I can not ping outside, I did not setup any policy.