SAVEAS is a dialog command. Meaning that when invoked a dialog pops up which you need to use. These kind of commands are 'killing' for automation using LISP. (or even *.scr)
In some cases this can be circumvented by turning dialogs off (like: filedia 0, for "open")
BUT, the guys at AutoDesk where kind enough to add a second version for these commands, using commandline prompts, instead of dialogs.
Usually you need to add a - before the command, to get the version without dialogs.
just like you add a . for the oem version (in case the command was redifined by user)
and the _ sign for the non-localized version (original commands are in English, but are translated with various languages)
In this case however its not a - but a + sign.
Enter it at the commandline: +saveas
then it will ask for the format: dwG dwT dwS dxF Other (note the CAPS, those are shortcuts)
After that it asks for a version: 2013 2010 2007 2004 2000 R14
Finally it will ask for a path/filename to save to, with a dialog! (yeah, don't ask me why)
I already mentioned it, but to prevent this file dialog to pop-up, you must set the sysvar FILEDIA to 0 first.
For that use (command "filedia" "0") -or use- (setvar "filedia" 0) <- prefered
To save the file as a ACAD 2013 DWG file:
(command "_.+saveas" "G" "2013" "C:/path/to/file.dwg")
; turn back on file dialogs with
(setvar "filedia" 1) -or- (command "filedia" "1")
So you need to adjust your current _.saveas line to:
(setvar "filedia" 0)
(command "_.+saveas" "G" "2013" "C:/path/to/file.dwg")
(setvar "filedia" 1)
...with the correct path & filename, of course.
Note: This does mean you need to know what the filename should be, as you need to supply one.