This is a sort of abridged version of the full install, but it should work for SP34. If it doesn’t get back to me.
Download this file
http://partnertechusa.com/files/PT-4000i/Drivers/Camera/Win2000/Plug-In/Sunplus/DRV/sp3x_32.dll
and move it to your windows/system (win 95, 98, me), winnt/system32 (win nt 4, 2000), windows/system32 (win xp) folder
If you’re on win 95, 98, or me, go to your windows folder and find the file named system.ini and add this line under the [system32] section
VIDC.SP34=SP3X_32.DLL
If you’re using win nt 4, 2000, or xp, open the registry editor. Go to start, run, then type regedit. Navigate to the key HKEY_LOCAL_MACHINE/SOFTWARE/Microsoft/Windows NT/CurrentVersion/drivers.desc make sure drivers.desc is highlighted on the left (selected)
right click anywhere on the right pane and create a new string value
right click it and rename it sp3x_32.dll
right click it again and choose modify
In the value data box type
Sunplus 32-bit AVI compression driver
Now navigate to the key
HKEY_LOCAL_MACHINE/SOFTWARE/Microsoft/Windows NT/Current/Version/Drivers32
(in many cases it’ll be the “folder” right underneath drivers.desc on the left)
make sure Drivers32 is highlighted.
in the same fashion, right click anywhere on the right and make a new string value
name it VIDC.SP34 and set its value to sp3x_32.dll
If this doesn’t work get back to me and I’ll give you a more thorough set of instructions. 
I am trying to view some old avi files I created with a webcam for my IBM Thinkpad. I am getting an error that SP34 codec is required, but I am having trouble finding this codec. Any suggestions would be greatly appreciated.
Thank you in advance.