Website causing CPU load.

So my web hosting company is going to shut down my website if I can’t fix the issue with my WordPress site.My site gets an average 300 view/day that I don’t think it’s very much,but my site is using 10% of their CPU according to this image that they sent to me
https://screensnapr.com/v/jlXC81.jpg
Their CPU is an Intel i7 x4x2(HT)x2.66 GHZ
I noticed that I’ve got problems with my plugins because i get errors:

[02-Mar-2012 12:42:18] PHP Warning:  in_array() [<a href='function.in-array'>function.in-array</a>]: Wrong datatype for second argument in /home/funcraft/public_html/wp-content/plugins/pie-register/pie-register.php on line 810
[02-Mar-2012 12:42:18] PHP Warning:  in_array() [<a href='function.in-array'>function.in-array</a>]: Wrong datatype for second argument in /home/funcraft/public_html/wp-content/plugins/pie-register/pie-register.php on line 815
[02-Mar-2012 12:42:18] PHP Warning:  in_array() [<a href='function.in-array'>function.in-array</a>]: Wrong datatype for second argument in /home/funcraft/public_html/wp-content/plugins/pie-register/pie-register.php on line 847
[02-Mar-2012 12:42:18] PHP Warning:  implode() [<a href='function.implode'>function.implode</a>]: Invalid arguments passed in /home/funcraft/public_html/wp-content/plugins/pie-register/pie-register.php on line 1320
[02-Mar-2012 13:04:03] PHP Warning:  preg_match() [<a href='function.preg-match'>function.preg-match</a>]: Delimiter must not be alphanumeric or backslash in /home/funcraft/public_html/wp-includes/media.php on line 1171
[02-Mar-2012 13:04:03] PHP Warning:  preg_match() [<a href='function.preg-match'>function.preg-match</a>]: Delimiter must not be alphanumeric or backslash in /home/funcraft/public_html/wp-includes/media.php on line 1171
[02-Mar-2012 13:04:48] PHP Warning:  preg_match() [<a href='function.preg-match'>function.preg-match</a>]: Delimiter must not be alphanumeric or backslash in /home/funcraft/public_html/wp-includes/media.php on line 1171
[02-Mar-2012 13:04:48] PHP Warning:  preg_match() [<a href='function.preg-match'>function.preg-match</a>]: Delimiter must not be alphanumeric or backslash in /home/funcraft/public_html/wp-includes/media.php on line 1171

I am really worried about this problem and I want to see if someone has got the same issues.I think there is a conflict between Mingle Forum and Pie Register but I am not entirely sure.Also I am not entirely sure neither if the plugins are what cause the load or something else.