Various Small Optimizations Plus A Couple Of Potential RTE Fixes

Optimizations:
1. Use Len(s) = 0 rather than s = ""
2. Use Len(s) <> 0 rather than Len(s) > 0
3. Use InStr before Replace
4. Use vbBinaryCompare instead of vbTextCompare when comparing against a static string

I also found a couple of places where there was a check against Nothing in the same conditional where the object was used. Because VB6 doesn't short circuit, those would both throw an RTE if the object ever was Nothing.