/pools/default/tasks returns 500 (Internal Server Error) - UI will display the yellow status bar too often

happens in a single node cluster while running smoke tests, seems like /pool/default/tasks returns error code 500

captured these from "chrome developer tools":

GET http://10.1.2.29:8091/pools/default/tasks?v=97202368&_=1327600575773 500 (Internal Server Error)
Failed to load resource: the server responded with a status of 500 (Internal Server Error)
cells.js:1169IOCenter.status.healthy: false
2app-misc.js:1173producing details cell for key: default , item:
Object
http://10.1.2.29:8091/pools/default/tasks?v=97202368&_=1327600567673Failed to load resource: the server responded with a status of 500 (Internal Server Error)
GET http://10.1.2.29:8091/pools/default/tasks?v=97202368&_=1327600575773 500 (Internal Server Error)
GET http://10.1.2.29:8091/pools/default/tasks?v=97202368&_=1327600588872 500 (Internal Server Error)
cells.js:1169IOCenter.status.healthy: true
GET http://10.1.2.29:8091/pools/default/tasks?v=97202368&_=1327600617592 500 (Internal Server Error)
cells.js:1169IOCenter.status.healthy: false
GET http://10.1.2.29:8091/pools/default/tasks?v=97202368&_=1327600622608 500 (Internal Server Error)

Request URL:http://10.1.2.29:8091/pools/default/tasks?v=97202368&_=1327600588872
Request Method:GET
Status Code:500 Internal Server Error
Request Headersview source
Accept:application/json
Accept-Charset:ISO-8859-1,utf-8;q=0.7,*;q=0.3
Accept-Encoding:gzip,deflate,sdch
Accept-Language:en-US,en;q=0.8
Authorization:Basic QWRtaW5pc3RyYXRvcjpwYXNzd29yZA==
Cache-Control:no-cache
Connection:keep-alive
Cookie:auth=QWRtaW5pc3RyYXRvcjpwYXNzd29yZA%3D%3D
Host:10.1.2.29:8091
Pragma:no-cache
Referer:http://10.1.2.29:8091/index.html
User-Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_2) AppleWebKit/535.7 (KHTML, like Gecko) Chrome/16.0.912.77 Safari/535.7
X-Requested-With:XMLHttpRequest
invalid-auth-response:on
Query String Parametersview URL encoded
v:97202368
_:1327600588872
Response Headersview source
Cache-Control:no-cache
Content-Length:44
Content-Type:application/json
Date:Thu, 26 Jan 2012 10:56:10 GMT
Pragma:no-cache
Server:Couchbase Server 2.0.0r-583-gdd9a9ea-enterprise

response :

["Unexpected server error, request logged."]
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