VM2 doesn't take orders anymore

[marceff]

Joomla 2.5.14 + VM 2.0.26 + Gantry 4 + php 5.3.10
Can't understand why, but VM doesn't take orders anymore and doesn't send either invoice or notification to client. I am still building and I always simulate purchasing by clients to check how it works. These days I was dealing with invoice issue.
Also the "add to cart" button doesn't work on presentation module in home page; it does work if get through product detail. At the end of purchase process, pressing "Confirm" it goes to select shipping / payment again and no email is sent by VM.
Could you please help to solve this issue? Thanks

[marceff]

Partly solves, as I checked the "Onepage checkout" without having the onepage software. But still have problems with "add cart" button on presentation product module as well as with product slide show both in homepage. It doesn't add product to cart- Any suggestion? Thanks