Fix Greek Language MySQL/ASP problem

We have a custom designed Greek Language ASP/MySQL ecommerce system, which works fine on the original server, but has now been moved to a new (shared hosting) server. We are having a problem with the encoding and some other issues: When I edit a product, the letters on the text (product descriptions, title etc.) change from proper Greek change to a different code. If I try to correct it by writing it again and then clicking save it goes to a white page with error 500. The same happens if I try to change the 'situation' of a product, for example to make a product out of stock. Also if I try to add a logo or a picture to the text it goes to a white page with error 500. You would be required to fix these problems. Time is short, so a quick and detailed response as to why we should pick you would be appreciated. Experience in Greek language, ASP, MySQL and HTML encoding/character sets would be required. Thanks for reading, Rob