>Hi,
>Should we tell the truth of our program bugs to our client? Or, we make a story/other excuses ?

I as a programmer would you answer YES.

It depend on your clients. If they understand that there is nothing like "bugfree", you may tell. Or look what successfull companies (IOW M$) is doing ...
It also depends on how fast you are able / willing to correct the error. (Or how proud you are ...)

Agnes