This message indicates that SketchUp Pro can't generate a license file in the shared folder that you created. To troubleshoot this issue, please try the following steps to test the the permissions of the shared folder:

Situation: every few minutes, an "invalid filename" message is displayed. SketchUp automatically saves your files while you are working on them, by default, every five minutes. This message is displayed when SketchUp is unable to write the auto-save file to the default location.

You may see this error when interacting with 3D Warehouse or Extension Warehouse from inside SketchUp. To resolve this issue, please follow these steps:

If a crash occurs when you are not connected to the Internet, BugSplat displays a dialog box indicating that a zip file has been created on your local hard drive. This dialog box also indicates the name and location of the zip file (normally AtLastCrashMMDDYY_HHMMSS.zip in your Windows temporary directory). Go to http://www.bugsplatsoftware.com/post/post_form.php and follow the instructions on the Web page to send this file to BugSplat software when you reconnect to the Internet.