Last night while working on a credit roll we ran into an intresting thing. First let me explain, we were sent a word Doc, which I opened into Illistrator and then cut from the one art board to anotheronce I had expanded it so the whole word doc showed. ( I don't understand this prosees either, because when i opena word doc in Illistrator I would assume the whole thing should come up but have found that many times I have to grab the bottom blue line of the object and pull it down to reveal the rest of the data, Any way that asside) Once I had every thing showing, and On an artboard sized properly for the entire role. I saved as a PDF file retained Illistrator editing ability and used no compression. The retaining of the editing copability is the only box on the save pop up I checked. I then shunted it across our network, but when we pulled it back into illistator all thetabs that had been there aligned the thing to the right in stead of their designated placements...
That is to say it opened into illistrator looking correct but any resizing of the text we did or any editing at all negated the tabes and right justified it as a defualt.
Saving PDFs from Illustrator have many problems and are generally much larger in size than printing to the acrobat PDF writer. Try to save your PDF by printing and chosoe Acorbat PDF for your printer driver, and saving to a PDF that way.
What font is losing their tabs? Try switching to another font.