Meteor-Files: Exception from sub Images

Hi

I got this kind of exception

Meteor.Files Debugger: [find(undefined)]
I20160409-16:15:55.655(2)? Exception from sub Images id GngR84PRRRtf9ZjhC Error: Match error: Failed Match.OneOf, Match.Maybe or Match.Optional validation
I20160409-16:15:55.655(2)?     at check (packages/check.js:138:15)
I20160409-16:15:55.655(2)?     at Files.Meteor.Files.Files.find (packages/ostrio_files/files.coffee:695:5)
I20160409-16:15:55.656(2)?     at Subscription._handler (server/init.js:10:26)
I20160409-16:15:55.656(2)?     at maybeAuditArgumentChecks (packages/ddp-server/livedata_server.js:1704:12)
I20160409-16:15:55.656(2)?     at Subscription._runHandler (packages/ddp-server/livedata_server.js:1026:17)
I20160409-16:15:55.656(2)?     at Session._startSubscription (packages/ddp-server/livedata_server.js:845:9)
I20160409-16:15:55.656(2)?     at Session.sub (packages/ddp-server/livedata_server.js:617:12)
I20160409-16:15:55.656(2)?     at packages/ddp-server/livedata_server.js:551:43
I20160409-16:15:55.657(2)? Sanitized and reported to the client as: Match failed [400]

thanks for help Best Regards Michal