Following the installation of the X version of adobe reader, saving a pdf file over the network handled by DFS (distributed system files) is not possible.
the following message appears: The file may be read-only or opened by another user. Save the document under a different name or in a separate folder.
Please refer to the thread http://forums.adobe.com/message/3312454#3312454
Reader X has known compatibility issues with DFS .
This should most probability be fixed in the nxt update of Reader X
Please note that disabling protected mode is not a workaround or solution to the problem.
Disabling Reader's protected mode may be harmful to your computer.