The following query produces a geoshape URL in which the space character has been encoded to the plus sign +:

select * where {
  wd:Q80967 wdt:P3896 ?goeshapeURL .
}

Result: http://commons.wikimedia.org/data/main/Data:Eilean+Siar.map

Observed: Clicking the link produces an error.

Expected result: http://commons.wikimedia.org/data/main/Data:Eilean_Siar.map

Two possible solutions:

1. encode space with underscore _
2. create redirects from plus-encoded URLs