1202: DOS read error in file <filename>
------------------------------------------------------------------------------

 This message indicates that DOS returned an error while reading an overlay
 file.

 A number of situations can cause this error to occur frequently and
 consistently:

 (1) The most common is the use of a 'file handles' routine within the
 program to increase the maximum number of file handles available to the
 program under DOS versions 3.0 to 3.2. If this 'file handle' routine is
 called after Blinker has opened the overlay file and loaded one or more
 overlays from the file, the file handle table is recreated, wiping out
 Blinker's existing file handle for the overlays. To avoid this, ensure that
 the handles function is called from the root before Blinker has loaded any
 overlays.

 CA-Clipper note:

 A combination of three factors can cause this to occur in a CA-Clipper
 application: (a) Calling one of these handle table expanding routines such
 as FUNCKY's SETHANDLES() or NETLIB's NHANDLES() from an overlay, (b) Using
 versions of DOS 3.3 or above, and (c) specifying the CLIPPER Fn environment
 parameter. Since the handle-increasing routine is only needed for DOS
 versions 3.0 to 3.2, this error can be avoided by checking the DOS version
 before calling that routine:

    IF DOSVERSION () < 3.3
       SETHANDLES (29) # a FUNCky, NetLib, or shareware function
    ENDIF

 (2) This error can also occur when non-overlayable modules are placed in the
 overlay area. If there are any .OBJ or .LIB files in the overlay area which
 are not known to be overlayable, then these should be moved to the root and
 the program relinked.

 If the program then runs successfully, this indicates that the file(s) are
 not currently overlayable (see the file 3RDPARTY.DOC on the distribution
 diskette for an up-to-date list of libraries which are known to be
 overlayable, or call our Technical Support BBS to download the latest
 version of 3RDPARTY.DOC).

 (3) Should the program stack overflow, it can overwrite the nearby file
 handle area, resulting in this error. Try increasing the size of the stack
 with either the STACK or BLINKER PROCEDURE DEPTH command.

 (4) A network could be configured to deny access to the .EXE once it had
 been loaded, preventing Blinker's overlay manager from reading an internal
 overlay. Also swap functions can result in this error if the file handle
 table has not been restored correctly.

 (5) If this error occurs sporadically, it is possible that the overlay file
 has been closed by an external influence such as a TSR or being logged off a
 network, or the overlay file has become corrupt because of a disk error and
 should be reinstalled.

 Note: The Blinker errors 1201 through 1204 can occasionally result from the
 effects of a virus, so if the above measures do not help then perform an
 extensive check for viruses and take the necessary measures for removal.