Need a bit more information. When you say it 'won't let you type in the description' - what happens when you try?

are you trying to list an item from a mobile phone?

There have been some strange things happening with eBay on IE lately.

Try this if you're using IE:

tools menu in Internet Explorer, then Compatibility View Settings, add ebay.com.au, ok. The screen will reload and should be OK if you weren't seeing it right/having problems.

If that doesn't work, try Chrome, which has less issues using eBay.