Hi Francisco,
Are all the CE system on UNIX. How is this directory \\CSPSASOLMAN\........ shared acorss the CE env. Can you please check the mount point has not be created using the guest user.
Please also check services that are used in windows related to sap is using guest.
Can you also please check that the what are the settings for RFC destination where SSO is used in the screenshot in the link.
http://wiki.sdn.sap.com/wiki/display/EP/EP7.3+-+CTS+Plus+configuration
Thanks
Rishi Abrol