Update to 3.4.0 triggers these errors

All was well until we updated from 3.3.6 to 3.4.0. After the update, a long list of error messages such as the examples below will precede the actual gallery. I tried the plugin on 2 different hosts with the same result. Rolling back to previous version fixes the errors.
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Warning: fopen(/a70c10467a833a2fc88f55199849eeed.cache) [function.fopen]: failed to open stream: Permission denied in …/plugins/flickr-justified-gallery/phpFlickr_a1/phpFlickr.php on line 188

Warning: fwrite() expects parameter 1 to be resource, boolean given in …/wp-content/plugins/flickr-justified-gallery/phpFlickr_a1/phpFlickr.php on line 189

Warning: fclose() expects parameter 1 to be resource, boolean given in …/wp-content/plugins/flickr-justified-gallery/phpFlickr_a1/phpFlickr.php on line 190

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