You're limited to having LabWindows installed on one machine at your workplace (which would include your office and your customer's site).
You can read the license agreement
here.
You have a couple of options:
1. Uninstall LabWindows from your desktop machine and install it on your laptop before you go to your customer's site. This really isn't as painful as it sounds, depending on how much you change the default options.
2. Talk to NI about a Debug License, which allows you to temporarily install software on a second machine for debug purposes.