In OpenOffice / Tools / Extension Manager does Alternative Searching show up as an installed Extension? If not, click on the Add button on bottom of that window and point it to the AltSearch.oxt file you have downloaded. I then had to restart Openoffice before there was an entry under
/ Edit / Alt Find and Replace which opens the Alt Find and Replace dialog.
12" of snow last night on 6" lying (left after 24" during last three weeks). Well stocked with food. Main road running slowly, but running. Car blocked in by 100yds drive covered by 12" snow. Plenty of food and oil. OK so long as electricity/phone don't fail.
Apache OpenOffice 4.1.2 on Xubuntu 16.04 (mostly 64 bit version) and infrequently on Win2K/XP