I am running 10 instances of the same package in parallel using dtexec. I have no pobs with that. There are articles on net saying there is a limit and also the variables inside the package acts weired when we do that. Is that right. I am not using regenerateID() which is mentioned at some places.

There were problems with memory management and the variables cross-pollinating early in the lifecycle of SQL 2005; however, those issues have been dealt with long ago. As to your other question, I don't know of any limit to the number of packages that can execute in parallel but I would be a bit reluctant to go too high. Each package will run within it's own memory space, allocating its' own threads, etc. Too many packages running on a system at one time can cause resource contention. Have you tried expanding it out to see what the practical limits are for your environment? What type of hardware are you running on?Please mark answered posts. Thanks for your time.