In order to provide a better answer, it would help if you could post the version of VI Logger you have (if you are not sure, you can find this out in Measurement & Automation Explorer under the Software folder) as well as the operating system you are using.
I am running VI Logger v1.1 on a Windows XP machine and the four buttons all work properly when viewing the graph of logged data. There is a known issue where the behavior you saw, with the "Beginning of Data" button not working, has appeared on a system that runs a German OS. If you are running a comparable OS then this behavior might occur and there is currently no fix for it.
If this is not the case for you then try to provide a little more information on your system and we can look into it further. T
hank you!
Regards,
Michael H
Applications Engineer
National Instruments
1-866-ASK-MYNI