Thank you for the reply.
I have the standard of standard downloaded (download tekkit 1.0.6 server from technicpack.net/tekkit/, unpack then run "launch.bat". Not even changed name of map from "world"). This means no extra mods or anything (why? since its only me and a close mate playing from time to time).
I recently solved this problem though through asking my friend to remove and then redownload his client verision of tekkit 1.0.6 and i removed and redownloaded the server package (download tekkit 1.0.6 server from technicpack.net/tekkit/, unpack then run "launch.bat").
The block breaking problem for him is now solved and no further problems have been found.
Sorry for wasting some of your time and thank you once againt for the reply.