Custom Actions upload error in 12.2

Hello!

I have error while uploading custom action in MII 12.2:

[005056A30000244C0000000D00001398] File could not be loaded. com.sap.xmii.temp.upload.17164.jar. Check error log for details.

There are 3 error and warning types in Log Viewer:

1) Could Not Find Assembly File GaCustoms.jar

2) MISSING_ASSEMBLY_FILE

3) *** MISSING RESOURCE: Unable to localize MISSING_ASSEMBLY_FILE

?