IM and Teleport Problems

Hi I have posted a query on resident chat too. I have a really irritating problem. I cannot IM many of my friends when they ar eat a distance from me and I cannot Teleport them to me. I have had an on-going series of problems with my Friends List for about three days - at one point friends were apparantly not on-line but actually were. I also seem to be having serious lag in flying. Is this problem a common one at the moment and what should I do if this persists. By the way my friends are not just "ignoring me" and actually think that I am ignoring them. Someone suggested I dump my cache which seems very complicated and rather drastic - can Linden "access" me and check me out? Like a doctor in real??Or at least tell me about a simple way to resolve my issues. Apparantly I am also invisible at time and have to re-bake a lot, I would welcome any advice. Jig C.