$conf['db_software'] = "$conf['db_software'] = ""; MySQLi"; MySQLi
Warning: Cannot modify header information - headers already sent by (output started at /home1/fdnyfish/public_html/pics/zp-core/functions-basic.php(113) : eval()'d code:1) in /home1/fdnyfish/public_html/pics/zp-core/reconfigure.php on line 36

Now I get this

$conf['db_software'] = "$conf['db_software'] = ""; MySQLi"; MySQLi

I was upgrading from 1.4.5.2 to 1.4.5.7

I downloaded and installed 1.4.5.2 and it works again.

Do I need to upgrade every update published?

Am I not allowed to skip versions?

Thanks

Remove the config file within /zp-data, save your credentials and re-run setup to let it re-create it.

Updates within bugfix/mantainance releases like 1.4.5.x should never be a problem (unless stated by us for some technical reasons). On updates from major versions likes 1.4.5.x to 1.4.6. that introduce new features it might be different. You will see it also as their release posts are quite detailed contrary to the bugfix release ones. This is also explained here:
http://www.zenphoto.org/news/installation-and-upgrading#release-number-info

When I remove the config file within /zp-data and try to re-run setup, mow I get a "ERROR 500 - INTERNAL SERVER ERROR" from my hosting company

here is my error log

[06-Nov-2013 01:29:04 America/Chicago] PHP Parse error: syntax error, unexpected T_ENCAPSED_AND_WHITESPACE, expecting T_STRING or T_VARIABLE or T_NUM_STRING in /home1/fdnyfish/public_html/pics/zp-core/setup/index.php(718) : eval()'d code on line 26
[06-Nov-2013 01:29:04 America/Chicago] PHP Notice: Undefined index: mysql_user in /home1/fdnyfish/public_html/pics/zp-core/setup/setup-sqlform.php on line 74
[06-Nov-2013 01:29:04 America/Chicago] PHP Notice: Undefined index: mysql_pass in /home1/fdnyfish/public_html/pics/zp-core/setup/setup-sqlform.php on line 78
[06-Nov-2013 01:29:04 America/Chicago] PHP Notice: Undefined index: mysql_host in /home1/fdnyfish/public_html/pics/zp-core/setup/setup-sqlform.php on line 83
[06-Nov-2013 01:29:04 America/Chicago] PHP Notice: Undefined index: mysql_database in /home1/fdnyfish/public_html/pics/zp-core/setup/setup-sqlform.php on line 87
[06-Nov-2013 01:29:04 America/Chicago] PHP Notice: Undefined index: mysql_prefix in /home1/fdnyfish/public_html/pics/zp-core/setup/setup-sqlform.php on line 92
[06-Nov-2013 01:29:04 America/Chicago] PHP Notice: Undefined index: mysql_prefix in /home1/fdnyfish/public_html/pics/zp-core/setup/setup-sqlform.php on line 95
[06-Nov-2013 01:31:50 America/Chicago] PHP Parse error: syntax error, unexpected T_ENCAPSED_AND_WHITESPACE, expecting T_STRING or T_VARIABLE or T_NUM_STRING in /home1/fdnyfish/public_html/pics/zp-core/setup/index.php(718) : eval()'d code on line 1
[06-Nov-2013 01:31:50 America/Chicago] PHP Notice: Undefined index: mysql_user in /home1/fdnyfish/public_html/pics/zp-core/setup/setup-sqlform.php on line 74
[06-Nov-2013 01:31:50 America/Chicago] PHP Notice: Undefined index: mysql_pass in /home1/fdnyfish/public_html/pics/zp-core/setup/setup-sqlform.php on line 78
[06-Nov-2013 01:31:50 America/Chicago] PHP Notice: Undefined index: mysql_host in /home1/fdnyfish/public_html/pics/zp-core/setup/setup-sqlform.php on line 83
[06-Nov-2013 01:31:50 America/Chicago] PHP Notice: Undefined index: mysql_database in /home1/fdnyfish/public_html/pics/zp-core/setup/setup-sqlform.php on line 87
[06-Nov-2013 01:31:50 America/Chicago] PHP Notice: Undefined index: mysql_prefix in /home1/fdnyfish/public_html/pics/zp-core/setup/setup-sqlform.php on line 92
[06-Nov-2013 01:31:50 America/Chicago] PHP Notice: Undefined index: mysql_prefix in /home1/fdnyfish/public_html/pics/zp-core/setup/setup-sqlform.php on line 95

Those messages make sense if there is no config file. Probably something with the permissions is not right on your host. Within zp-core you find a template file of the config files. Use that to create one manually.

Permissions issues could indeed be the source of both issues.

I deleted the setup folder and reuploaded it

Installed fine after that

1.4.5.7 is installed