Issues with Extremely Slow DB Queries and bootstrap.inc

Hello,

I am currently experiencing very slow page loads on my website due to a few database queries that take an incredible amount of time. The most common are associated with the function DrupalDatabaseCache:set where queries like:

INSERT INTO cache_menu (cid, serialized, created, expire, data) VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1, :db_insert_placeholder_2, :db_insert_placeholder_3, :db_insert_placeholder_4)

and

UPDATE cache_bootstrap SET serialized=:db_update_placeholder_0, created=:db_update_placeholder_1, expire=:db_update_placeholder_2, data=:db_update_placeholder_3 WHERE ( (cid = :db_condition_placeholder_0) )

take ~2500ms and happen multiple times in the course of one page load. Typical pages look like this: "Executed 82 queries in 18043.09 ms.Page execution time was 20568.44 ms." I gathered this information using the Devel module.

In addition to this issue, it seems like there might be an issue with bootstrap.inc.

I ran several SSH commands including:

time php index.php and strace php index.php

Both commands output an error:
<b>Notice</b>: Undefined index: SCRIPT_NAME in <b>/home1/orianbre/public_html/swingsyndicatedance/includes/bootstrap.inc</b> on line <b>1379</b><br />

Here is the output from the trace:

<b>Notice</b>:  Undefined index:  REMOTE_ADDR in <b>/home1/orianbre/public_html/swingsyndicatedance/includes/bootstrap.inc</b> on line <b>2488</b><br />
) = 160
poll([{fd=3, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
write(3, "\25\2\0\0\3INSERT INTO watchdog (uid, "..., 537) = 537
read(3, "\t\0\0\1\0\1\374a\2\2\0\0\0", 16384) = 13
chdir("/home1/orianbre/public_html/swingsyndicatedance"

Both commands seem to indicate a problem with the bootstrap.inc file.

I also encountered this error:

<li><em class="placeholder">Notice</em>: Undefined index: REQUEST_METHOD in <em class="placeholder">_block_render_blocks()</em> (line <em class="placeholder">824</em> of <em class="placeholder">/home1/orianbre/public_html/swingsyndicatedance/modules/block/block.module</em>).</li>

What should I make of all this? Thank you for the help.