HELP needed with database password!

[Dave]

For some odd reason, my database is prompting me for a
database password, and I havent even set one. I am
running the database on a network with all the users
viewing it via Access Runtime, and some times I would use
it on the full version of Access whilst it was being used
on runtime. The simple answer is that someone is setting
the password without my knowledge but I don't think that
would be possible on the runtime versions. I dont know
whether running the database on two machines in runtime
would cause a problem but I am stumped as to why the
database is doing this. Any suggestions?
Dave.