This continues to mess with my brain (an admittedly easy task!).

Several of our sites are getting
PHP Warning: strlen() expects parameter 1 to be string, array given in /home/site_name/public_html/includes/functions/functions_general.php on line 152
Commonalities are minimal other than all sites effected are 1.3.9h and all debug files to the cache directory are timestamped at the conclusion of an order. All have IH2 and Fual Slimbox. Some have captcha and newsletter subscription, but we get the error on sites with neither, just one, or both of those mods.

Whether the site is using AIM, PayPal, Ceon's offline, or some other payment module seems to make no difference. AND, only occasionally does any site throw this error. One site has 25+ orders this month with a mixture of PayPal and AIM. Only two orders (one for each) has thrown the error.

We have checked and re-checked for current PayPal and AIM files along with other payment mods.

No changes have been made to customer database settings or files gathering/forwarding customer data.

If it would JUST BREAK already, we could fix it.

Any suggestions of other things we might check would be GREATLY appreciated.