Has error -- Unable to add ... to the Web. ... Access is denied.

Problem
While using Visual Studio 2005 Copy Web Site function, received this type of error on some files:
Has error -- Unable to add 'MyFolder/MyFile.aspx' to the Web. Unable to add file 'MyFolder\MyFile.aspx'. Access is denied.

Solution
Found that files had been manually copied by another developer and had "Read Only" attribute set. Removed "Ready Only" and it worked.