Problem installing FAX in XP SP2

Hello to all ...

I'm using a Xp Sp2 and an external 56K faxmodem 3com/usrobotics.
I want to installa the fax capabilities, XP at starting found the modem
and install it, after this i go to Control Panel/Install
application/Install windows components to add fax service.
During install a message told me that some file related to fax cannont
copy (the files already exists), i told it to continue in any case ...
at the end it says that the procedure is complete but i don't find no
fax in "printer and fax" and i if return in Control panel/Install
application/install windows components the fax check box in unchecked.
I try this operation again but with no result and no news error appear
during this fase.

I also tried to run this script i found on internet:

set obj = CreateObject("FaxControl.FaxControl.1")
If not obj.IsFaxServiceInstalled then
WScript.echo "Installing Fax Service..."
obj.InstallFaxService
obj.InstallLocalFaxPrinter
elseif not obj.IsLocalFaxPrinterInstalled then
WScript.echo "Reinstalling Fax Printer..."
obj.InstallFaxService
obj.InstallLocalFaxPrinter
else
WScript.echo "Fax printer is ready to go."
end if

and it reporting this error:
"Porta specificata sconosciuta"
80070704

corresponding on this script row:
obj.InstallLocalFaxPrinter

i try also to run this .reg file

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Rpc\ClientPr otocols]
"ncacn_np"="rpcrt4.dll"
"ncacn_ip_tcp"="rpcrt4.dll"
"ncadg_ip_udp"="rpcrt4.dll"
"ncacn_http"="rpcrt4.dll"

and then re execute the script before... but nothing ...

now what can i do ?

Thanks in advance and excuse me for my terrible english ...

Fabio