Hello, Ana:
Oh, I’m so sorry! I misread your initial post and missed that it was Pages '09 you were working with. My sincerest apologies.
We have not fully tested it, but from what we’ve been hearing from customers it should work ok with Pages '09 on Mavericks.
I recommend testing with a different document. If it happens in any document, contact our Support team and we’ll see if we can work out why. If it happens with only a specific document, you may want to copy and paste your text into a new document. Please note you’ll likely have to redo the references – sorry about that – but it ought to correct the crashing.