>i may not be able to use at() here the same error may appear twice or more in the text .if one of the items already selected i need to select next error
You can either specify that you want to go to the 2nd., 3rd., etc. occurence; or you can search from a certain position on. I don't remember if at() permits the second option, and I don't have VFP with me right now; if not, you will have to search in a substring.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)