WordPress Plugin API error during installation
When I was logged into WP (2.8.5) and I tried to install a new plugin (from the dashboard), I would get the following error:
“An Unexpected HTTP Error occured during the API request.”
Basically, according to WP user efree_unix,
The cause of error is too long in the process of requesting the API plugin in the wordpress server so that the operation timed out. By default, wordpress give 5 seconds time limit to request a plugin. If within 5 seconds does not get a replay, then the process will be stopped and displayed an error “An Unexpected HTTP error occurred during the API request.”
THE SOLUTION:
Open wp_include/http.php file on line 223
‘timeout’ => apply_filters( ‘http_request_timeout’, 5),
change the script above into
‘timeout’ => apply_filters( ‘http_request_timeout’, 30),
You may refer to efree_unix's post at here. At least it works for me 
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