You wish to create an HTML doc using <<HTML; that requires interpolation.

An @import (style sheet) or email address may be included. If the '@' symbol is not escaped, an error message will be returned that refers ONLY to the first line of the here-is

Global symbol "@import" requires explicit package name at /usr/local/a
+pache/..... line 100.
Execution of /usr/local/apache/.... aborted due to compilation errors.
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Knowing the above helps to quickly locate the problem. (or avoid it)