The XP machines are probably 32-bit. Your Windows 7 computer you said is 64-bit. 32-bit drivers are not compatible with 64-bit drivers and vice versa.
What you need to do is from one of the XP computers, open the name of the Windows 7 computer from Start -> Run: ex. \\windows7
You should see a listing of shares on the Windows 7 computer (if you have anything shared). Open Printers & Faxes. Next right click anywhere in that window and select properties. There should be a new window that loads. Select the printer drivers tab at the top. Then click on Add printer driver. Now select the 32-bit Savin printer driver you are using and let it install on the Windows 7 computer.
Make sure that all of the XP computers are using the exact same 32-bit Windows XP driver. They must all use the same version and release date. It helps to download the latest 32-bit driver first and install it on all of the XP computers. Save the driver to a temporary folder then follow the directions in the first paragraph. You only need to do this one of the XP computers. After that, all of the XP computers should be able to have their Savin printers loaded when using RDP.
I run into this problem a lot with SBS2008 and SBS2011 (both are 64-bit OS) with older XP Pro workstations that my clients won't upgrade/replace. Took me a lot of searching to figure out how to get it working.
https://www.wincert.net/tips/window...t-drivers-on-windows-server-64bit-or-x64