This is the error log from server
2011/05/11 17:40:02 [error] 3358#0: *1 FastCGI sent in stderr: "PHP Fatal error: require() [<a href='function.require'>function.require</a>]: Failed opening required 'context.core.inc' (include_path='.:/usr/local/lib/php') in ˆ×®
on line 3" while reading response header from upstream, client: 220.255.1.81, server: mydomain.com, request: "GET / HTTP/1.1", upstream: "fastcgi://unix:/var/run/php5-fpm.sock:", host: "mydomain.com"
2011/05/11 17:40:05 [error] 3358#0: *1 FastCGI sent in stderr: "PHP Fatal error: require() [<a href='function.require'>function.require</a>]: Failed opening required 'context.core.inc' (include_path='.:/usr/local/lib/php') in x¯
on line 3" while reading response header from upstream, client: 220.255.1.81, server: mydomain.com, request: "GET / HTTP/1.1", upstream: "fastcgi://unix:/var/run/php5-fpm.sock:", host: "mydomain.com"
2011/05/11 17:45:08 [error] 3383#0: *1 no user/password was provided for basic authentication, client: 220.255.1.85, server: mydomain.com, request: "GET /install.php HTTP/1.1", host: "mydomain.com"
2011/05/11 17:50:22 [error] 3383#0: *115 FastCGI sent in stderr: "PHP Fatal error: require() [<a href='function.require'>function.require</a>]: Failed opening required 'context.core.inc' (include_path='.:/usr/local/lib/php') in ØŠú
on line 3" while reading response header from upstream, client: 220.255.1.52, server: mydomain.com, request: "POST /admin/build/modules/list/confirm HTTP/1.1", upstream: "fastcgi://unix:/var/run/php5-fpm.sock:", host: "mydomain.com", referrer: "http://mydomain.com/admin/build/modules/list/confirm"

My using linode server, nginx 1.0.2 / php 5.2.17 / php-fpm / mariadb 5.2
If i purge nginx 1.0.2 and install back 0.8.54 the drupal context work. I also try with a fresh install of drupal and only install context modules and i getting error with nginx 1.0.2