I assume that you are wanting to send a page when a mailbox receives a message, an urgent message perhaps. In order to do this, the mailbox must first be in a class of service that has Call Me enabled. Next, you will need to setup the Call Me rules within Subscriber Options. When setting this up, if the outbound dial string is more than 20 characters, including commas for pauses, you need to insert an apostrophe. For example:
9,1,8005551234,,1234&,,5551234567
This has something to do with maximum string size, so the apostrophe concatenates the strings together. For further info on how to set up the subscriber options, I am pretty sure they have some documentation on that on the support.avaya page.