With php 5.6 I get: FastCGI process exited unexpectedly

After numerous gyrations I finally have gotten my site up and working. The problem we have run into is the site constantly breaks when using php 5.6. The version it is working on now is 5.3, but the site runs extremely slow. My hosting company cannot figure this out. This is the latest they have sent when they explored the issue:

The FastCGI process exited unexpectedly
Faulting application name: php-cgi.exe, version: 5.6.22.0, time stamp: 0x57468660
Faulting module name: MSVCR110.dll, version: 6.3.9600.18233, time stamp: 0x56bb4e1d
Exception code: 0xc0000135
Fault offset: 0x0009d3c2
Faulting process id: 0x6798
Faulting application start time: 0x01d29cf0872c8c27
Faulting application path: PHP56\php-cgi.exe
Faulting module path: MSVCR110.dll
Report Id: c52300cd-08e3-11e7-811a-00155d042a03
Faulting package full name:
Faulting package-relative application ID:

If anyone has any idea on how to resolve this I would appreciate your sharing that wisdom immensely.

Site is midwestglobalgroup.com, running Zen Cart 1.5.5b (recently upgraded to this which is when my problems began). "Payeezy JS" payment module, php version 5.6. MySQL 5.1.63

HTTP Error 500.0 - Internal Server Error
C:\Program Files (x86)\Parallels\Plesk\Additional\PleskPHP56\php-cgi.exe - The FastCGI process exited unexpectedly

Most likely causes:
IIS received the request; however, an internal error occurred during the processing of the request. The root cause of this error depends on which module handles the request and what was happening in the worker process when this error occurred.
IIS was not able to access the web.config file for the Web site or application. This can occur if the NTFS permissions are set incorrectly.
IIS was not able to process configuration for the Web site or application.
The authenticated user does not have permission to use this DLL.
The request is mapped to a managed handler but the .NET Extensibility Feature is not installed.

Things you can try:
Ensure that the NTFS permissions for the web.config file are correct and allow access to the Web server's machine account.
Check the event logs to see if any additional information was logged.
Verify the permissions for the DLL.
Install the .NET Extensibility feature if the request is mapped to a managed handler.
Create a tracing rule to track failed requests for this HTTP status code. For more information about creating a tracing rule for failed requests, click here.

Detailed Error Information:
Module FastCgiModule
Notification ExecuteRequestHandler
Handler php-5.6.22
Error Code 0xc0000135
Requested URL (Path to my admin panel deleted)
Physical Path D:\Domains\(Path to my admin panel deleted)
Logon Method Anonymous
Logon User Anonymous

More Information:
This error means that there was a problem while processing the request. The request was received by the Web server, but during processing a fatal error occurred, causing the 500 error.
View more information »

Microsoft Knowledge Base Articles:

294807

1. A "500 Internal Server Error" is extremely generic ... and that's intentional because it's designed to not let hackers/attackers know what bug/vulnerability they might have tripped, if any, for example. Described more here: Why am I getting 500 INTERNAL SERVER ERROR messages?

Any prudently-configured server will actually record in the server's logs EXACTLY why a 500 error (or any other fatal/security error) has occurred.

2. In your case it's probably a permissions issue. Consult the server administrator to know what limitations they've imposed related to file permissions. For example, during installation, the configure.php files need to be made writable. But due to the varied number of ways a server can be configured, most documentation or install instructions suggest making those configure.php files be as liberally-writable by the widest possibility of users/processes on the server as possible. But many servers will instantly halt if they discover files that are set to such liberal permission. ONLY YOUR HOST CAN HELP YOU SET THAT CORRECTLY ... but of course, setting the configure.php files to the same permission as other files such as index.php is an ideal place to start.
NOTE: In IIS the issue of "permissions" relates both to "writable or not" as well as permissions for each specific "user" on the server. Your control panel (Plesk you mentioned) probably gives you access to that. But if higher privilege is needed, your hosting company has control.

3. It could also be that you've got some partial/missing/incomplete/damaged files on your server as a result of transferring files for the upgrade. It's always prudent to double-check that in case something went amuck that you didn't catch.

In fact, a full compare of all files on the server vs what files you "expected" to be on the server can be very revealing: both in what did/didn't make it during transfer, as well as any leftover artifacts or extras, or even unauthorized things you might find.

4. Further reading: https://www.zen-cart.com/wiki/index....Obscure_Issues

Thank you Dr. Byte. I'll get with my hosting co. tomorrow and dig into this.

My hosting company discovered they had some files missing. They fixed this and we are up and running.