i downloaded a theme from symbianthemes.com and it claimed that i works on 3650/3660.
when i tried installign the .sis file, the screen pops up a message and says "series60skinsupport" required....

what does it mean?
does it mean i cannot install any themes?

Yinyang series 60 theme for nokia

View the Link (http://www.handango.com/brainstore/PlatformProductDetail.jsp?siteId=308&catalog=0&sectionId=0&productType=2&platformId=4&productId=118582)

Themes in a *.SIS format will not work in 3650/3660 as it is running the wrong version of the handset software.

These themes are for 6600, 7610 & maybe the new N-Gage!

If symbianthemes.com advised you that it would work, speak to them so they can support it.

if .sis wouldnt work, then which file type would it work with? where can i download those?

There are only 3rd party theme apps for 3650.

This has been covered before, Please search the forum.