The syntax "@PAGE@" is one of the replacement patterns. If DokuWiki finds such an expression within the raw text of a page it will substitute them by the related information (the page name in this case). That has nothing to do with parameters handed over to plugins. Plugins usually have their own syntax and internal processing of values/switches. Mostly they do not allow the DokuWiki replacement patterns within their own syntax to prevent mismatch of substitutions.
PS:
Does this question handle the same issue as your
plugin rater post ?
Please prevent asking the same question within multiple subs of the forum.