A quick
Google search indicates that you should be using the sis900.o module.
This article on SuSE's support site documents one possible problem, and the fix. As the article suggests, check your /etc/modules.conf file (it may be /etc/conf.modules) to see which module is associated with the network adapter.
Depending on the distro and version you are using, support for the sis900 chipset is probably built into the kernel, but if you're using an older version of Linux, you may have to obtain and install the corect driver as a loadable module.