OK. The repository structure has directories "src" "aux" and "script". No "trunk", no "tags", no "branches". Is there any way I can get this code into a correctly-structure repository while preserving the revision history?
Yes, there is a way. You should use svn mv.
mkdir trunk
mkdir branches
mkdir tags
svn ci
svn mv src trunk/src
svn mv aux trunk/aux
svn mv script trunk/script