🚀 go-pugleaf

I am working on an installation tool running under Windows 3.0.
The tool will be delivered on a floppy and must be run by "win
a:\run\install" (without quotes of course), or within Windows via
the program- or filemanager.
After loading the program a problem is raised: if the tool asks
to insert the first diskette in drive A: and the right floppy is
inserted, Windows generates a system error message "Cannot read
from drive A:". This occures at the SDK-function 'OpenFile()' to
open a file on drive A: and for all floppy's other than the
original one were the tool is started from.
Conclusion: the (operating) system does not detect a change of
a floppy.

I have made all segments (code+data) and all resources
(dialogboxes, stringtable, icons, etc) PRELOAD and FIXED.
Windows 3.0 is running on a 386-machine in enhanced mode under
MS-DOS 4.01.
The problem does not arise on all 386-machines and never if the
tool is started up from the harddisk.
All floppydrives have 'change line support'. We suspect it is a
timing problem were possibly the hardware interrupt 0Eh has no
effect. Is there anyone who can confirm or refute this suspicion?

Does anyone know, or has anyone a hint how to solve this problem?

Thanks in advance,

Marco