No error log that I can see in the root of the XF directory or data/internal_data - does it put it somewhere specific?
The apache error log just the Premature End of Script Headers, pasted below:
[Mon Dec 20 08:47:48 2010] [error] [client 94.6.206.3] Premature end of script headers: index.php, referer: (DOMAIN)/forums/install/index.php?install/step/1b
[Mon Dec 20 08:47:48 2010] [error] [client 94.6.206.3] File does not exist: /home/ijeffers/(DOMAIN)/internal_error.html, referer: (DOMAIN)/forums/install/index.php?install/step/1b
[Mon Dec 20 08:49:09 2010] [error] [client 94.6.206.3] File does not exist: /home/ijeffers/(DOMAIN)/forums/install
[Mon Dec 20 08:49:09 2010] [error] [client 94.6.206.3] File does not exist: /home/ijeffers/(DOMAIN)/missing.html
[Mon Dec 20 08:51:23 2010] [error] [client 94.6.206.3] File does not exist: /home/ijeffers/(DOMAIN)/(DOMAIN)
[Mon Dec 20 08:51:23 2010] [error] [client 94.6.206.3] File does not exist: /home/ijeffers/(DOMAIN)/missing.html
[Mon Dec 20 08:51:24 2010] [error] [client 94.6.206.3] File does not exist: /home/ijeffers/(DOMAIN)/(DOMAIN)
[Mon Dec 20 08:51:24 2010] [error] [client 94.6.206.3] File does not exist: /home/ijeffers/(DOMAIN)/missing.html
[Mon Dec 20 09:11:30 2010] [error] [client 94.6.206.3] Premature end of script headers: index.php, referer: (DOMAIN)/forums/install/index.php?install/step/1b
[Mon Dec 20 09:11:30 2010] [error] [client 94.6.206.3] File does not exist: /home/ijeffers/(DOMAIN)/internal_error.html, referer: (DOMAIN)/forums/install/index.php?install/step/1b
[Mon Dec 20 09:14:09 2010] [error] [client 94.6.206.3] Premature end of script headers: index.php, referer: (DOMAIN)/forums/install/index.php?install/step/1b
[Mon Dec 20 09:14:09 2010] [error] [client 94.6.206.3] File does not exist: /home/ijeffers/(DOMAIN)/internal_error.html, referer: (DOMAIN)/forums/install/index.php?install/step/1b
[Mon Dec 20 09:17:24 2010] [error] [client 94.6.206.3] Premature end of script headers: index.php, referer: (DOMAIN)/forums/install/index.php?install/step/1b
[Mon Dec 20 09:17:24 2010] [error] [client 94.6.206.3] File does not exist: /home/ijeffers/(DOMAIN)/internal_error.html, referer: (DOMAIN)/forums/install/index.php?install/step/1b
[Mon Dec 20 09:51:35 2010] [error] [client 94.6.206.3] Premature end of script headers: index.php, referer: (DOMAIN)/forums/install/index.php?install/step/1b
[Mon Dec 20 09:51:35 2010] [error] [client 94.6.206.3] File does not exist: /home/ijeffers/(DOMAIN)/internal_error.html, referer: (DOMAIN)/forums/install/index.php?install/step/1b
[Mon Dec 20 10:48:01 2010] [error] [client 94.6.206.3] Premature end of script headers: index.php, referer: (DOMAIN)/forums/install/index.php?install/step/1b
[Mon Dec 20 10:48:01 2010] [error] [client 94.6.206.3] File does not exist: /home/ijeffers/(DOMAIN)/internal_error.html, referer: (DOMAIN)/forums/install/index.php?install/step/1b
[Mon Dec 20 10:55:18 2010] [error] [client 94.6.206.3] Premature end of script headers: index.php, referer: (DOMAIN)/forums/install/index.php?install/step/1b
[Mon Dec 20 10:55:18 2010] [error] [client 94.6.206.3] File does not exist: /home/ijeffers/(DOMAIN)/internal_error.html, referer: (DOMAIN)/forums/install/index.php?install/step/1b
(replaced domain to keep it private)