[Plugin: Fast Secure Contact Form] Fatal error: Allowed memory size

Sorry for my bad english. Two questions:
1) I’m running WP version 3.04, with this plugin, and ‘Broken Link Checker’ -normally deactivated-, ‘Google XML Sitemaps’ and ‘Limit Login Attempts’, all of them upgraded to last version.
My site is in a shared hosting -with Asmallorange.com-.
I see in the dashboard area the same error for the WP developer blog, Incoming links and Plugins boxes:

Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 122880 bytes) in /…/…/public_html/wp-includes/class-simplepie.php on line 14908

I’ve deactivated all the plugins and then tried to activate one by one: the culprit is Fast Secure Contact Form.
I have 2 forms in my site, and they seem to work well.
I had implemented time ago the wp-config.php lines:
define(‘WP_MEMORY_LIMIT’, ’64M’);
but this is not a solution.
The parameters in php.ini are ok, like you suggest for your plugin, including:
memory_limit = 64M
Other parameters modified from the default in php.ini are:
allow_call_time_pass_reference = Off
disable_functions = dl,system,exec,passthru,shell_exec,proc_close,escapeshellcmd,proc_open
ignore_user_abort = On
expose_php = Off
display_errors = Off
display_startup_errors = Off
register_long_arrays = Off
register_argc_argv = Off
magic_quotes_gpc = Off
file_uploads = Off
upload_max_filesize = 7M
allow_url_fopen = Off
extension=php_openssl.dll
date.timezone = “Europe/Paris”

I’ve even tried to add
ini_set(‘memory_limit’,’64M’);
to the top of the cache.php file, after the initial <?php but to no avail.

class-phpmailer.php and class-smtp.php, in the wp-includes folder, are version 5.1, downloaded from phpmailer.sourceforge.net
I don’t remember exactly why I put these updated files there, maybe trying some other contact-form plugin, but don’t think this will be significant.

jquery.js, in the wp-includes\js\jquery folder, is version 1.5, downloaded from jquery.com (the same occurs with previous version 1.4.2)

wp-config.php is not placed in the public_html directory -the same as WP-, but in the previous root directory.

What do you think can be the cause of these errors?

2) I like your plugin, because I privilege the security in my site. But I don’t need the CAPTCHA function. What folders and/or files can I avoid to upload to my server if I don’t need this function? (captcha-secureimage folder takes about 1,5MB). Must I also change or comment some line in some php file of you plugin to achieve this?

Many thanks in advance