If you have a synaptics touchpad and the xorg synaptics driver is loaded before you "startx", then xorg "confless" might find the driver and load it automatically and it might set SHMConfig=true.
..but I doubt it.
To check, could you have a look in /var/log/Xorg.0.log after you "startx" and search for "synaptics"- if there is no mention of "synaptics" in the log, then the driver is not loaded and synclient will not work and you will need to create an xorg.conf in order for it to work.
You might be able to create a suitable xorg.conf by doing the following after exiting xorg: $ sudo su
# Xorg -configure
If you paste the resulting xorg.conf here, I can suggest modifications to enable synaptics.