There is probably a corrupt graphic (likely) or font (less likely) in the document. The best way to figure out where it is is to use the "divide and conquer" method:
Create a PDF of the first half of the document, and see if it is successful. Do the same for the last half. Which ever one fails, you know which half the error is in. Continue to divide the pages and create PDFs of each half. With a few repetitions, you'll see which page the error is on.
If it's not obvious, on the page where the error is, temporarily remove a graphic and create a PDF of the page until you find the offending graphic. Open the graphic in the appropriate application: Resave an image as a PSD file, or an Illustrator graphic as an AI file.
If it's a corrupt font, it would show up on all pages. In that case, replace the font.
the document exports fine as two halves. it crashes when i try to export it as one large file
The simplest solution would be to use Acrobat Pro to combine the two halves.
In recent Acrobat versions, choose File > Combine Files into a Single PDF.
ill try it out thx
i tried to edit a paragraph of text on a later page, and it would immediately crash indesign when i tried to click on it. u were right and there was messed up font or something, i retyped the text and now it works fine. it didnt show up when i tried to export as pdf in 2 parts tho thx