Thank you for your post.
When you say it "does not work on the web", can you be a little more specific? That is, when you enter the number of shares, does the information disappear after the record is committed? Does the wrong information get posted in a particular field? "X" information appears in FileMaker Pro, but "Y" information appears in Instant Web Publishing?
Any additional information would be helpful in narrowing down the possible cause(s).