I have created a form using Acrobat X Pro. I am going back into the form to edit some links that have changed. When I select edit text, I am able to delete characters, but not add characters. This is both on the hyperlink text and in the general text for the form. I can open and edit the text in Acrobat 9 Pro, but would prefer to use X as it is the standard for the office and the one I created the document in originally. I am on a Mac OX 10.6.8 system.
Sorry, but your post did not make it clear to me that the form had been created on the same MAC, but that you were simply trying to edit on a MAC. In any case, check the document properties to see what fonts are included in the PDF and if that might be the issue. Also, if you have set the form up for distribution, then you will have to use the Save A Copy (I think that is what it is on X) to reset the form for editing.