Here are my gzip configure:

gzip on; gzip_min_length 1k; gzip_proxied expired no-cache no-store private auth no_last_modified no_etag; gzip_buffers 16 8k; gzip_http_version 1.0; gzip_comp_level 9; gzip_window 8k; gzip_hash 16k; gzip_types text/plain application/x-javascript text/css application/xml; gzip_vary on; gzip_disable "MSIE [1-6]\.";

Please notice I'm using gzip_window & gzip_hash.I tried many times to change the value of those arguments.It's no matter of gzip_buffers and other arguments but gzip_window & gzip_hash.When I changed with different value combination of these two arguments I got different error logs about gzip:

...preallocated memory: 16384 of 8192 while... ...preallocated memory: 5824 of 57344 while... ...preallocated memory: 32768 of 8192 while... ...preallocated memory: 65536 of 8192 while... ...preallocated memory: 5824 of 14336 while... ...preallocated memory: 5824 of 49152 while...

btw:I compiled nginx-0.7.28 with Cygwin under Windows XP professional.