AVDocSaveOptimized not working in Acrobat standard

hello,

i want to save the documents to PDF 1.7v from any of the higher versions.

                                                  ASPathName asSourcePath=ASFileAcquirePathName(PDDocGetFile(pdDoc));

                                                  AVDoc avdoc1 = AVDocOpenFromFile( asSourcePath, ASGetDefaultFileSys(), NULL);

                                                  PDFOptParamsRec opts;

                                                  ASText t = ASTextFromPDText("Standard");

                                                  AVGetOptimizerParamsForPreset( t, avdoc1, &opts);

                                                  opts.asPathDest = asSourcePath;

                                                  opts.fileSys = NULL;

                                                  opts.enmAcrobatVersion = kPDFOptAcrobat8;

                                                  opts.enmObjectCompression = PDSaveRemoveASCIIFilters | PDSaveAddFlate | PDSaveOptimizeContentStreams | PDSaveReplaceLZW | PDSaveOptimizeFonts | PDSaveOptimizeXObjects;

                                                  opts.enmObjectCompression=kPDFOptPartialComp ression;

                                                  DURING

                                                  AVDocSaveOptimized(avdoc1, &opts);

this program is working fine in Acrobat x Pro. but it fails in Acrobat standard. What may be the reason? how can we make it to work in Acrobat Standard.?