I have the same problem. It appeared unexpectedly without any code changes.
HTTP log goes here:
GET http://opensocial.msappspace.com/proxy/relay.proxy?opensocial_url=http%3A//ys-got.cow.nikitova.com/game/my/auth%3Frpctoken%3DupXgpzeCziWZABlIZpDLXIWxjXQ81bRgYWjtc60Nbxh3GBZjzkzV5h7V_pl_2VQIH68mEw0a5oX_sl_6BpDoZSordcb4gek8mQ908sNWRzQYpSKNc_eq_%26from_id%3Dmyspace.com.person.568213696&opensocial_authtype=SIGNED&opensocial_app_url=&ts=1307546558716 HTTP/1.1
Host: opensocial.msappspace.com
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.17) Gecko/20110420 Firefox/3.6.17
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Proxy-Connection: keep-alive
X-OpenSocial-Authorization: OPENSOCIAL opensocial_token="upXgpzeCziWZABlIZpDLXIWxjXQ81bRgYWjtc60Nbxh3GBZjzkzV5h7V+2VQIH68mEw0a5oX/6BpDoZSordcb4gek8mQ908sNWRzQYpSKNc="
Content-Type: application/x-www-form-urlencoded
Referer: http://opensocial.msappspace.com/1.0/app/203942/render/canvas?country=ua&installState=0&lang=en&mc=UOC&oauth_consumer_key=http%253A%252F%252Fwww.myspace.com%252F444791946&oauth_nonce=3356438&oauth_signature_method=HMAC-SHA1&oauth_timestamp=1307632956&oauth_version=1.0&opensocial_surface=canvas&os_token=upXgpzeCziWZABlIZpDLXIWxjXQ81bRgYWjtc60Nbxh3GBZjzkzV5h7V_pl_2VQIH68mEw0a5oX_sl_6BpDoZSordcb4gek8mQ908sNWRzQYpSKNc_eq_&perm=%5b%22%22%2c%22BI%22%2c%22FL%22%5d&v=dev&v=dev&oauth_signature=iJ7zHj0%2f59%2fMFIqd7TP6DCM3b8c%3d
Cookie: MSCulture=IP=195.242.151.5&IPCulture=en-US&PreferredCulture=en-US&PreferredCulturePending=&Country=VUE=&ForcedExpiration=0&timeZone=0&myStuffDma=&myStuffMarket=&USRLOC=QXJlYUNvZGU9MCZDaXR5PUtpZXYmQ291bnRyeUNvZGU9VUEmQ291bnRyeU5hbWU9VWtyYWluZSZEbWFDb2RlPTAmTGF0aXR1ZGU9NTAuNDMzMyZMb25naXR1ZGU9MzAuNTE2NyZQb3N0YWxDb2RlPSZSZWdpb25OYW1lPTEzJkxvY2F0aW9uSWQ9MA==&UserFirstVisit=1; __utma=86614470.1510043414.1307116741.1307116741.1307361583.2; __utmz=86614470.1307361583.2.2.utmcsr=myspace.com|utmccn=(referral)|utmcmd=referral|utmcct=/games/play/148378; __utmc=86614470
HTTP/1.0 500 Internal Server Error
Date: Wed, 08 Jun 2011 15:22:49 GMT
Server: Microsoft-IIS/6.0
X-Powered-By: ASP.NET
X-AspNet-Version: 4.0.30319
Cache-Control: private
Content-Type: application/json; charset=utf-8
Content-Length: 87
X-Cache: MISS from gw001k.nikitova.com
Via: 1.0 gw001k.nikitova.com (squid/3.1.12)
Connection: keep-alive
{ "errorMessage" : "The remote name could not be resolved: 'ys-got.cow.nikitova.com'" }