If this is the 'This file may not be save if it contains code that was
intended to harm your computer' dialog, there are two ways to prevent it on
your PC.
1) Change your macro security level to 'Low'. (Tools, Macro, Security). But
be aware that this will apply to all Access files you open on that PC.
2) Digitally sign the code. You'll find a program called 'Digital
Certificate for VBA Projects' in your 'Microsoft Office Tools' program
group. This creates a certificate which can be trusted only on the PC on
which it was created.
If you're developing apps for other uses, all of whom log on to the same
domain, the network administrator can create a certificate for you that can
be trusted on that domain. Otherwise, you'll need to ask your company to buy
a certificate from a commercial CA. (There's a link to a list of CAs in the
dialog.)
In theory, you're supposed to be able to obtain a Class II, 'Individual
Developer' code-signing certificate. In practise, however, to the best of my
knowledge - and I have done some research into the question - no CA is
currently providing those certificates.
