Enable the 8.3 naming convention on the ePO server.
NOTE: Installation to a path 
that failed before 8.3 naming was enabled will still fail to that 
same path. Point the installation to a new directory path, because 8.3 
naming support is added to that path by default when enabled.
  
To enable the 8.3 naming convention:
Click Start, Run, type regedit, and click OK.
Navigate to, and select, the following registry key:
 
 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem]
  
Right-click NtfsDisable8dot3NameCreation, and select Properties or Modify (depending on your version of Windows).
Modify the Value data from 1 to 0.
 
 NOTE: On Windows Server 2008 the default value is 2; you must change it to 0.
  
Restart your computer.
Verify the 8.3 naming convention is enabled on the drive: 
- Click Start, Run, type cmd, and click OK.
 Type the following command and press ENTER:
 
 dir /x
 
 You should see that folders now have a column for short names, for example, Progra~1 for Program Files. 
  
- Type exit and press ENTER.
 
Now you can install ePO to a new directory.