Build error but not on view/review

i’m trying slate and the api documentation page comes up successfully but when i

bundle exec middleman build --verbose

i get some successes but mostly errors. below is example of an error i am getting off one file but it includes the index.html file, etc. so never generates much.

   identical  build/images/navbar.png
   identical  build/images/logo.png
== Request: /fonts/slate.svg
== Finishing Request: fonts/slate.svg (0.0s)
       error  build/fonts/slate.svg
undefined method `try' for "image/svg+xml":String
Did you mean?  tr
               tr!
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/middleman-core-4.0.0/lib/middleman-core/e
xtensions/minify_javascript.rb:54:in `call'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/middleman-core-4.0.0/lib/middleman-core/e
xtensions/minify_css.rb:60:in `call'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/middleman-core-4.0.0/lib/middleman-core/m
iddleware/inline_url_rewriter.rb:40:in `call'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/middleman-autoprefixer-2.7.0/lib/middlema
n-autoprefixer/extension.rb:48:in `call'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/rack-1.6.4/lib/rack/head.rb:13:in `call'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/rack-1.6.4/lib/rack/lint.rb:49:in `_call'

C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/rack-1.6.4/lib/rack/lint.rb:37:in `call'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/rack-1.6.4/lib/rack/builder.rb:153:in `ca
ll'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/rack-1.6.4/lib/rack/mock.rb:74:in `reques
t'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/rack-1.6.4/lib/rack/mock.rb:56:in `get'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/middleman-core-4.0.0/lib/middleman-core/b
uilder.rb:165:in `output_resource'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/middleman-core-4.0.0/lib/middleman-core/b
uilder.rb:95:in `each'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/middleman-core-4.0.0/lib/middleman-core/b
uilder.rb:95:in `output_files'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/middleman-core-4.0.0/lib/middleman-core/b
uilder.rb:59:in `run!'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/middleman-cli-4.0.0/lib/middleman-cli/bui
ld.rb:65:in `build'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/thor-0.19.1/lib/thor/command.rb:27:in `ru
n'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/thor-0.19.1/lib/thor/invocation.rb:126:in
 `invoke_command'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/thor-0.19.1/lib/thor/invocation.rb:133:in
 `block in invoke_all'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/thor-0.19.1/lib/thor/invocation.rb:133:in
 `each'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/thor-0.19.1/lib/thor/invocation.rb:133:in
 `map'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/thor-0.19.1/lib/thor/invocation.rb:133:in
 `invoke_all'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/thor-0.19.1/lib/thor/group.rb:232:in `dis
patch'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/thor-0.19.1/lib/thor/invocation.rb:115:in
 `invoke'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/thor-0.19.1/lib/thor.rb:40:in `block in r
egister'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/thor-0.19.1/lib/thor/command.rb:27:in `ru
n'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/thor-0.19.1/lib/thor/invocation.rb:126:in
 `invoke_command'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/thor-0.19.1/lib/thor.rb:359:in `dispatch'

C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/thor-0.19.1/lib/thor/base.rb:440:in `star
t'
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/middleman-cli-4.0.0/bin/middleman:23:in `
<top (required)>'
C:/Ruby23-x64/bin/middleman:23:in `load'
C:/Ruby23-x64/bin/middleman:23:in `<main>'