to clarify, since I had missed that nimxs is launched by the ni service mxssvr: to restore normal functionality of the driver it suffices to do as root:
/etc/init.d/nipxirmu stop
/etc/init.d/nidevldu stop
/etc/init.d/nipal stop
/etc/init.d/mxssvr stop
/etc/init.d/mxssvr start
/etc/init.d/nipal start
/etc/init.d/nidevldu start
/etc/init.d/nipxirmu start
