This helped a friend of mine with the same problem. A lot of info (cut-and-pasted), skip down to the useful part:
"Error: 1311 source file not found cd drive\\...
Published date: 2003-03-07
ID: TS65415
Applies to:
AutoCAD® 2004
AutoCAD® 2000i
AutoCAD LT® 2004
AutoCAD LT® 2002
AutoCAD LT® 2000i
Issue
When you try to install the software, one of the following errors messages is displayed:
Error: 1311 source file not found cd drive\\... acad1.cab
Error: 1311 source file not found cd drive\\... aclt1.cab
Solution
This error occurs because there is a problem with the Microsoft® Windows® Installer program used by the software. It produces this error when the registry entry AllocateCDRoms at the following subkey is set to a value of 1:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
Use one of the following methods to resolve this problem.
Method #1
Warning! Problems caused by improperly editing the Windows registry could render your computer operating system unusable. Microsoft provides a wealth of critical information that you need to know about the registry in the Microsoft Knowledge Base at
http://support.microsoft.com/support.
Use the Microsoft® Registry Editor only at your own risk and only after backing up the registry as well as the system.dat and user.dat files as outlined for your operating system in the Microsoft Knowledge Base and in the related solution, TS66513. Additional information about the registry is also contained in the Help topics in the Microsoft Registry Editor.
Start the Registry Editor and locate the following subkey:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
Change the value for the AllocateCDRoms entry to 0.
Exit the Registry Editor.
For more information about the AllocateCDRoms registry entry, see Microsoft Knowledge Base article 172520.
Method #2
Copy the source files from the install CD to the local hard disk drive.
Run the setup.exe file from the local hard disk. "
Good luck! Here's the URL if you're interested:
http://usa.autodesk.com/adsk/servlet/ps/item?siteID=123112&id=2898908&linkID=2475323
