What's the exact error message you're getting?  (Side note: it's always better to just cut-n-paste the message, rather than trying to paraphrase it in your own words. Sometimes, programs generate similar but distinct error messages. Knowing the exact wording helps those who want to help...)

For example, just in case your specific instance of Imager wouldn't have truetype support, the error message would be:

Cannot load /usr/local/fonts/arial.ttf: Font type not found
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Is that maybe the message you're getting?

The docs say that you can test for truetype support like this:

use Imager;
print "Has truetype\n" if $Imager::formats{tt};
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Just an idea...