I too have been having problems with creating a sale with Promotions Manager. Just tried it now and still not responding. Ebay says they are aware of it and will be working on it. 

Have also been trying to create a sale with the new revised Markdown Manager. Even that one was not working, you may have 1 or 4 items go into sale, instead of at least 500 items. Have been finding that buyers had been turned off when you can't create a sale using a percentage off on one item. Had found with Promotions Manager the only way use it was to create a sale where the buyer had to purchase more than 1 item to get a markdown. They want to get a sale on one item, not more than 1.

After contacting ebay today about not been able to create a sale, was told there was a glitch stopping me from creating a sale and ebay will look into it. Created another sale today using the Markdown Manager and was able to get a number of items into sale. Unfortunately I will have to wait at least a week to include others as I had reduced prices to increase sales. The old system worked very well and the new one does not increase your chance of getting a sale using a markdown.