Toolbox - Drop File Error

We are having a problem when dragging and dropping Toolbox parts. Our
browser configuration is set to "No Copy (always use master part file).
The Toolbox resides on a server with all the related folders and files
given full Read/Write access to all the users. The users can place
parts fine from the Toolbox. But, if a different user comes in after
someone has already placed a part, as soon as they choose the same part
class, they get an error message stating that the part is still being
modified. As long as they choose parts that have not been placed, it
works fine. Once the first user to place the part exits their assembly,
the restricted part and then accessible by the next user.

Has anyone experienced this same problem or know what our problem my
be?

Thanks

 

The toolbox folder should be read-only not read/write.

Jeff