The problem with saving documents seems to occur often with Windows Vista OS (full text can be fount at: http://support.microsoft.com/kb/931277):

"This problem occurs if the hard disk drive or the flash device was formatted in an earlier version of the Windows NTFS file system. For example, this problem occurs if the drive or the device was formatted from Microsoft Windows XP."

There are several workarounds.

Method 1: Run the program that you use to save the file as an administrator

1) Right-click the shortcut that starts the program, and then click Run as Administrator to start the program. If the Run as Administrator option is not available, follow these steps:

- Right-click the shortcut that starts the program, and then click Properties.
- Click the Shortcut tab, and then click Open File Location.
- Right-click the executable file for the program, and then click Run as Administrator to start the program.

Note. If the program was installed by using an .msi package file, you must locate the executable file for the program to run it as an administrator. For example, a shortcut to a Microsoft Office program does not include the Run as Administrator option.

2) Save the file.

Method 2: Save the file to the Documents folder and then move it to the destination folder

1) Save the file to the Documents folder.
2) Right-click the file that you saved in step 1, and then click Cut.
3) Click Start, click Computer, right-click the destination folder, and then click Paste.
4) Type the administrator password when you are prompted.