can't save on networkfolder

I am using Mathcad Release 15.0 and Datecodeunknown

The user can not save on Network folder. He can create and save data in Windows explorer on the network folder so permmissins are ok. but when he have the save dialog from mathcad 15 he receive an message that he must save under new name and when he gives a new same message to use other new name

Here are the errors that I faced
save under differentname