504 bad time gateway

[yarre]

Hi
I have a shop on joomla 2.5.6 and VM 2.0.8e. Shop have 9 categories, in each category about 20 products and above - 90 products.
As soon as the number of products began about >200 i see this - 504 bad time gateway. This error appear only in admin panel and i don't enter in some category, don't edit some products!

Support says that this error appear only becouse in high-loading processor -  99%

Please, help me

I fix this problem! it's easy - in adminpanel go to VM settenigs - settings - tab number 2 backend view - max quantity of products per page <40. If number 200 - this problem appear now
i'm happy, tnx VM team!