is ' or " different in MS-Word then ascII?

Hello, This question may border on OT... I have a web form where visitors must enter large amounts of text at one time (text area). Once submitted, the large amount of text is stored as a CLOB in an Oracle database. Some of my visitors create their text in Ms-Word and then cut and paste it into the text area and then submit the form. When I retrieve it from the database, I do a stripslahses, htmlentities and nl2br in that order to preserve the format of the submitted test. When I view this text, single or double quotes show up as little white square blocks. I've tested this out with MS-Word on a windows machine and a mac machine. Same thing happens with either OS. This only happens when they cut and paste from MS-Word into the text area. If they type text into the text area directly, everything is fine... I know I can search through their submitted text and swap out the unrecognized character and insert the proper one. I just don't know what to look for as being the unrecognized character. I've googled all over looking at ascII charts and keyboard maps. Nothing mentions MS-Word specific information though. Anyone out there dealt with this before? Thanks, R