From MS:

CAUSE
This behavior can occur when Windows encounters an internal overflow of the stacks that are used by 32-bit Windows-based device drivers. Please note that this is not related to the "Stacks=" line in the Config.sys file, which is used for 16-bit MS-DOS-based device drivers.

Stack overflow conditions are indicative of errors in the device driver. Device drivers are allocated 4 kilobytes (KB), or one page, of space to be used as a stack. If the device driver uses more than 4 KB of memory, a stack overflow condition occurs.

Windows sets aside a number of extra memory pages, or spare stack pages, to be used temporarily so that your computer does not stop responding (hang) due to a stack overflow condition. When the stack overflow condition has passed, Windows reclaims the temporary page. The default number of spare stack pages is two.

If Windows detects that it has run out of spare stack pages, you receive the error message that is mentioned in the "Symptoms" section of this article. Windows continues to operate correctly unless a device driver encounters a stack overflow condition when there are no free spare stack pages.

RESOLUTION
To resolve this behavior, add the following line to the [386Enh] section of the System.ini file, and then restart your computer:

MinSPs=4
If the behavior continues to occur, increase the number of spare stack pages in increments of 4 (for example, 8, 12, 16).

NOTE : Each spare stack page requires 4 KB of memory.

To edit the System.ini file for Windows 95, 98 and 98se:
Click Start , click Run , type sysedit in the Open box, and then click OK .


Click System.ini on the Window menu.

In the [386Enh] section, type the following line:

MinSPs=4
On the File menu, click Exit , and then click Yes to save the changes.

Restart your computer.