Hotmail sometimes sends a page with an error on it, so I cannot access anything. How to fix

There's no specific amount of time. If you use your Outlook.com account for a while (basically showing Outlook.com that you're not a spammer), Outlook.com will figure out that you're not a spammer and automatically increase your quota.

Alternatively, you can verify your account by going to http://sms.live.com and verifying your mobile number (no need to sign up for notifications - simply verifying your mobile number will work).

From what I've read here, and here, everything indicates that you can't add back your original myname@hotmail.com, or at least not right now, but you might have some options:

1. Wait for a rather longer amount of time, until the address is free and create a new account with it. (Not a new alias because it won't let you.) This period can vary from 30 days to 1 year. The thing is that in the mean you'll have to let everyone know that your address is another one.

2. Pretend that you've been hacked and try to convince MSN costumer help to revert your account status to a date before the alias was deleted. To do this, it's IMPORTANT to first BACK UP all your e-mail, contacts and calendar because there is also a chance that the account could get blocked permanently. To back up all e-mail, I would move the mail on every folder (including Sent and Archived) to Inbox and then access the original account with Gmail or Thunderbird through POP. You might need to create an alias ending in @outlook.com for your screwed up Microsoft account. It might be also a good idea to ask to revert the status of your account from a different IP location (as if your computer were compromised and had so many virus that it became a zoo...)

The second method is riskier but you'd be able to recover your myname@hotmail.com faster.

Let us know how everything turned out.