cat > test.sh <<EOF
#!/bin/sh
rm -f test.repo
rm -rf test; mkdir test; cd test
fossil new --date-override "1980-01-01T00:00:00+0" ../test.repo
fossil open ../test.repo
:> test; fossil add test
fossil ci --date-override "1980-01-01T00:00:00+0" -m "Check in test file."
fossil version
EOF

"sh test.sh" output follows:

project-id: 06dc47045026a113d202f6ebf85807a699ef5ca1
server-id:  8e1bc7871007ca8338c67b15012ca24229ac7bea
admin-user: asau (initial password is "36c4b4")
ADDED  test
New_Version: dfa15dfb77b49b84dd6cd95663bf5daee5413fec
fossil: manifest file (3) is malformed
This is fossil version [61ca4141cc] 2010-08-18 17:27:25 UTC

drh added on 2010-08-19 11:47:51:
Fossil uses the SQLite date/time parsing routines and those routines do not recognize the +0 timezone suffix. Fossil has now been updated to output an error when an unrecognized date is handed to --date-override.