Thank you for posting.
The first thing to check is whether a genuine license key conflict is occurring. If you click "Info" under "About FileMaker Pro" from the menu, it should display the license key currently in use. Verify that each machine is using a different license key or a single volume license key.
Next, does this issue only occur on a single database or does it happen regardless of the database you connect to?
Lastly, the issue could be related to the client machines themselves. To test whether it is a preferences or configuration issue, try creating a new user on each machine.
Thank you for your prompt response. I have checked all the license numbers and they are all different. I tried a new user account and same problem. I reinstalled the Filemaker Application on the client computer and no luck. I have reloaded the server application numerous times and has not helped. It has nothing to do with my databases. Most recently, all I have loaded are the sample databases that come with Filemaker Server. When I paid yesterday for tech support, they advised downloading a trial version of Filemaker 11 which I assume would help as I assume it would have a different license key. However, the versions of Filemaker that are being used on the plagued laptop computers are Filemaker 10 that are only 6 months or less old and an upgrade isn't exactly fair. The problem is only happening on the computers that are wireless. All wired computers have no problem and 2 wireless computers have no problem. All are being logged in from a local site. Now what???