Internal error while exporting the products and categories list (via export\import tool)

[sipan]

so my opencart version is 1.5.4
I have an export\import tool, that was working ok.
but now I resieve error message when I press "export" button.

error: "500 Internal Server Error. The server encountered an internal error or misconfiguration and was unable to complete your request...."

there is no any error message in logs.

Any ideas?

[opencart]

don;t post here! you need to contact the developer of the extension. if they don;t reply try my support staff by using the contact us form at the top of the opencart.com web site.