This tool runs only in meterpeter context.
Is ready for run in backtrack 4 

THe default path for portscanner is de following

/pentest/windows-binaries/scanners/sl.exe

The path where usualy are meterpreter scripts is the following

/pentest/exploits/framework-3.2/scripts/meterpreter/

there are a few way for run it

my favorite
run pivot-scan -a

Other way

run pivot-scan -r 192.168.1.1-192.168.1.10
but in this case you must know the network

EXAMPLE

meterpreter > run pivot-scan -a
[*] Created by Augusto Pereyra aepereyra at gmail.com
[*] Uploading Portscanner
[*] Performing portscanning for IP range 192.168.1.1-192.168.1.254
[*] Transmitting intermediate stager for over-sized stage...(191 bytes)

192.168.1.3,"",0,0,"Yes","139 445 12345","123 137 138 445 500"
192.168.1.10,"",0,0,"Yes","7 9 13 19 135 139 445 12345","7 9 137 138 161 445 500 1027"
192.168.1.9,"",0,0,"Yes","135 139 445 1433 8080 12345","137 138 445 500 1434"
192.168.1.14,"",0,0,"Yes","7 9 13 19 135 139 1433","7 9 137 138 500 1434"
192.168.1.16,"",0,0,"Yes","7 9 13 19 135 139 445 12345","7 9 137 138 161 445 500 1027"
192.168.1.18,"",0,0,"Yes","21 23 25 80 515","69 137 138 161"
192.168.1.23,"",0,0,"Yes","135 139 445 1025 1755 3372 6666","135 137 138 445 500 1027"
192.168.1.178,"",546,0,"Yes","
443","7 9 11 53 68 69 111 123 135 137 161 191 192 256 260 407 445 500 514 520 1009 1024 1025 1027 1028 1030 1033 1034 1035 1037 1041 1058 1060 1434 1645 1646 1812 1813 1900 1978 2002 2049 2140 2161 2301 2365 2493 2631 2967 3179 3327 3456 4045 4156 4296 4802 5631 5632 11487 31337 32768 32769 32770 32771 32772 32773 32774 32775 32777 32778 32779 32780 32781 32782 32783 32784 32785 32786 32787 32788 32789 32790"
192.168.1.201,"",0,2,"Yes","","53 67 68 69 123 137 138 161 514 520 1812"
192.168.1.210,"",0,0,"Yes","","68 161 1025"
meterpreter >     


Enjoy!
Augusto Pereyra
aepereyra at gmail.com