The policies concerning donations have changed and PayPal is looking at users and how they are implementing their donation item button code.
Here's a bit more info:
In the past this was not an issue as probably 1000's of people currently have donation buttons on their web sites and blogs and they are not nonprofits or registered 501(c)(3) organizations, just individuals. Things have changed as there's new tax laws to deal with, accounts must be verified, etc. All US financial institutions such as banks, credit card issues and 3rd party transaction processors such as PayPal are required by law to reasonably verify the identity of the person behind any and all Accounts into which money is collected.
As stated by PayPal.
"This button is intended for fundraising. If you are not raising money for a cause, please choose another option. Nonprofits and or must verify their status to withdraw donations they receive. Users that are not verified nonprofits must demonstrate how their donations will be used, once they raise more than $10,000."
One easy option is to use a Buy Now item button. You can code it so an amount can be entered right on the PayPal Screen. You can also use the the Shipping Override Variables so as not to charge any shipping if you have a shipping method setup for other purposes. Using a Buy Now type button allows people to give you funds without having a PayPal Account. Note, you would still pay the standard transaction processing fees, same as selling an item and you must have either a Premier or Business Account, a Personal Account won't work.
Another easy option would be to have people use the send money feature. Of course they would have to have a PayPal Account and if they send the funds as a gift assuming they don't use a credit card, there would be no fees unless the funds are being sent out of the country.
Another work around for donations is to use a 3rd party service like this one:
http://www.gofundme.com/
If you are a US Resident, this service sends the funds directly to your bank account or you can request a paper check, no middleman.
If you don't live in the US, then a PayPal Account is requried. You can withdraw your funds to your PayPal Account Balance. Note, this looks like a transfer of funds as you are not collecting funds thru your PayPal Account.
