ofxEdsdk-EDS_ERR_DEVICE_BUSY error under the win

anyone using kyle’s ofxEdsdk with EOS550D or EOS450D under windows b4? having some trouble with it,its running after 15 or 30mins then throws exceptions of "an error is in download live pixel EDS_ERP_DEVICE_BUSY inside Download Evf " rather than giving images. any help&thoughts? cheers!