It is hard to know what might be going wrong. It sounds like perhaps the vectors are generally in the right place, but when you zoom in, you can see that they are slightly off. Is that right? If so, then the problem may be that the georeferencing for either the image or the vectors specifies the wrong datum. If you can provide more detailed information about the image and vector files (their formats, what projections and datums they use, how you imported them into ENVI, etc.) and exactly what you are seeing that is not correct, we may be able to offer some suggestions. - Peg