There is no xoops_version.php and even no other files just as per zip extracted. But still same error. thanks
When it is intermittent, that means there is a race condition or some termination, or work overload, .. that influences normal processing. Are there errors like eg timeouts, in the logs from IIS or database?
You do not have the error with 2.2.6?
No. It is one of the reasons why the module does not exists error could show, when the preference is not empty and the module there does not exists.