When you test your application, you see subscriptions appearing with (null) as the price, for example, "1 Year Subscription for (null)". Or, Apple rejects your iTunes Connect application submission for the same reason. Or, your application submission is rejected because a subscription price appears as 0.00, but there is a length associated with it. (For example, subscription appears as "1 Year Subscription for 0.00 €".)
Currently, the Viewer Builder is incapable of producing a Viewer app with In-App Purchases of type Free Subscription that passes Apple's requirements. (This type of subscription includes showing no time length, and no price or unexpected (null) value for a price.)
Some users have reported cases where their Retail Auto-Renewable Subscriptions have shown (null) as the price in their testing. Examination of the communications with Apple's servers showed that the request for In-App Purchases information (shown as subproducts in the server query) returned an empty array. Apparently, later testing produced the expected results with no change on the side of the DPS publisher. If you are certain that your subscriptions are retail, not free, and you are seeing (null) instead of the price tier, and the issue does not resolve itself within 2-3 hours, contact Apple for assistance.
Apple introduced the In-App Purchase type Free Subscription late in the iOS 5 development (documented in the iTunes Connect Developer Guide version 7.2, October 17 2011). This purchase type was introduced after the iOS 5 compatible version of Viewer Builder (version 1.5.1) was completed. Adobe hopes to provide an update to the Viewer Builder that supports this In-App Purchase type soon.