Well,

If they are in the same file, then you can leave the package name out, else you have to include it.

our-variables, are file-scoped, if you use them in another file then they are out of scope, and then you need to refer to the symbol table where they are in (Header:: in your case).

Also, if you want a global variable which is module-scoped (not file-scoped as our), then you should use: use vars qw/$var1 @array1 %somehash .../;

Update (after reading the previous post): If the vars are exported then you can use them without the package name. Since export really means that the thingie you export are imported in the currenct namespace.