vb.net - Acrobat API reading text from a specific area -

i have piece of code worked fine 3 years. i'm not sure happened server made stop working. reads text in funky characters !..||+$% instead of actual text.

i'm using vb.net , windows forms in visual studio 2010 acrobat pro can use api. please me.

dim objpdfpage acropdpage dim objpdfdoc new acropddoc dim objpdfavdoc new acroavdoc dim objacroapp new acroapp dim objpdfrecttemp object dim objpdfrect new acrorect dim textrangecount integer dim objpdftextselection acropdtextselect dim temptextcount long dim strtext string = ""  dim pagecount integer = 0 dim pageindex integer  dim itemname string = ""  dim column integer = 0  objpdfdoc.open(txt_path.text) pagecount = objpdfdoc.getnumpages  pageindex = 0 pagecount - 1     'get pages in pdf document     objpdfpage = objpdfdoc.acquirepage(pageindex)      'get page real size     objpdfrecttemp = objpdfpage.getsize      'draw rectangle around area want read     objpdfrect.left = 50     objpdfrect.right = objpdfrecttemp.x - 350     objpdfrect.top = objpdfrecttemp.y - 300     objpdfrect.bottom = 650      'select text in rectangle area     objpdftextselection = objpdfdoc.createtextselect(pageindex, objpdfrect)      ' text of range     try         temptextcount = objpdftextselection.getnumtext         textrangecount = 4 objpdftextselection.getnumtext             'get item number , exit loop             'itemname = itemname & " " & objpdftextselection.gettext(textrangecount - 1)             itemname = objpdftextselection.gettext(textrangecount - 1)             exit         next     catch ex exception         msgbox("this error message rectangle around text. " & ex.message)         objpdfdoc.close()     end try      'set array contain item number , page number     setarray(pageindex, itemname) next