open the pdf there. they have a straighten command in fact you can click on one point at top left corner and then draw a line either to bottom left corner of the pdf Make sure it to the corner of the page (not the background) or to top right corner of the page. then it will twist the whole page enough to straighten it. Then re-save as a PDF. Then you can use it in acrobat. Would be a good feature for Acro 10 or 11. If the designer of Graphics Converter can do must not be terribly complex, to program.
1. if it's a scanned document then 'Optimise Scanned PDF' under the
Document menu will attempt to correct (only if there's just one scanned
object on the page)
2. Use the touch-up object tool, right-click and then 'rotate selection'