Check COMx: properties in PERIPHERAL SETUP inside BIOS.

Com 1 configured at 3F8h----IRQ4 in Bios.
I can e-mail the program in question less than 1 MB

How was the program accessing ports in the older setup? Maybe it was looking for COM2 _ Your current bios setup seems correct.

Nope--COM1
Old laptop was running Win98

You should also try configuring COM passthrough for DOSBox (I had never used it, heh). Edit dosbox.conf inside the folder where you have DOSBox installed. BUT IT DOES NOT WORK UNDER OFFICIAL DOSBOX 0.63 - YOU MUST USE SOME CVS VERSION LIKE Ykhwong's

E.g. This is an excerpt.

[serial] # serial1-4 -- set type of device connected to com port. # Can be disabled, dummy, modem, directserial. # […]
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[serial]
# serial1-4 -- set type of device connected to com port.
# Can be disabled, dummy, modem, directserial.
# Additional parameters must be in the same line in the form of
# parameter:value. Parameters for all types are irq, startbps, bytesize,
# stopbits, parity (all optional).
# for directserial: realport (required).
# for modem: listenport (optional).

serial1=directserial irq=4, startbps=19200
serial2=dummy
serial3=disabled
serial4=disabled

This seems to work for me.

PS - Program also works for me running it natively under WinXP SP2.