Problem: Referential Integrity Constraints lost

Hi i think a hit a major problem on 7.2.1.
I run 3 systems with postgresql 7.2.1.
Its a redhat 7.1 for development, a redhat 7.3 for production
and a FreeBSD 4.6.1RC2 for testing.

After long runs (with periodic (daily) vacuum analyze's)
i noticed that some of the triggers that implement referential integrity
constraints just disapeared.
Some of these triggers were still present on the FreeBSD system
(which has been idle for a month or so), whereas on the linux
systems they were absent.

Has any one have a clue??
Any comment would be really valuable at this moment of darkness.

Thanx.

==================================================================
Achilleus Mantzios
S/W Engineer
IT dept
Dynacom Tankers Mngmt
Nikis 4, Glyfada
Athens 16610
Greece
tel:    +30-10-8981112
fax:    +30-10-8981877
email:  achill@matrix.gatewaynet.com
        mantzios@softlab.ece.ntua.gr