These are likely things you have tried but in case...

I would make sure that the strings have had the Trim function applied. I would try putting the data fields inside a text box and then set that text box to left justifiy.

If you are setting the justification at the field level and trimmed out any empty left and right spaces it should be working.... Any general setting for center justification should be overwritten by the field level settings.

Do you have the most recent Crystal Merge Module dlls installed on the web server?  That might have been the resolution I found, but I just can't remember for sure.