First I would upgrade to 1.7.4 to see if that fixes it. We also have 1.7.5 due out very soon.
1.8 final should be around soon, but due to some major changes in database abstraction it might not be as stable as the 1.7 family.
If you try the 1.7.4 upgrade and let me know. I might be able to get a fix in for 1.7.5 with your help.