StringIndexOutOfBoundsException errors, possibly a problem loading Mission Equipment Storage

[assaultdoor]

Using MML 0.47.7 on OS X with Java build 1.8.0_51-b16, I get the following error in the logs:

Error parsing null!
java.lang.StringIndexOutOfBoundsException: String index out of range: -1
at java.lang.String.substring(String.java:1967)
at megamek.common.loaders.BLKFile.getLegacyVariableSize(BLKFile.java:119)
at megamek.common.loaders.BLKBattleArmorFile.loadEquipment(BLKBattleArmorFile.java:261)
at megamek.common.loaders.BLKBattleArmorFile.getEntity(BLKBattleArmorFile.java:158)
at megamek.common.MechFileParser.parse(MechFileParser.java:204)
at megamek.common.MechFileParser.(MechFileParser.java:85)
at megamek.common.MechFileParser.(MechFileParser.java:77)
at megamek.common.MechSummaryCache.loadMechsFromDirectory(MechSummaryCache.java:565)
at megamek.common.MechSummaryCache.loadMechsFromDirectory(MechSummaryCache.java:524)
at megamek.common.MechSummaryCache.loadMechData(MechSummaryCache.java:237)
at megamek.common.MechSummaryCache.lambda$getInstance$0(MechSummaryCache.java:86)
at java.lang.Thread.run(Thread.java:748)

This may or may not be related to a similar error I get when loading any BA design created under an older version of MML that used the old fixed-weight "Mission Equipment Storage" equipment:
*** Unable to load file: megamek.common.loaders.EntityLoadingException: Exception from class java.lang.StringIndexOutOfBoundsException: Str$
at megamek.common.MechFileParser.(MechFileParser.java:94)
at megamek.common.MechFileParser.(MechFileParser.java:77)
at megamek.common.MechSummaryCache.loadMechsFromDirectory(MechSummaryCache.java:565)
at megamek.common.MechSummaryCache.loadMechsFromDirectory(MechSummaryCache.java:524)
at megamek.common.MechSummaryCache.loadMechData(MechSummaryCache.java:237)
at megamek.common.MechSummaryCache.lambda$getInstance$0(MechSummaryCache.java:86)
at java.lang.Thread.run(Thread.java:748)

MML simply refuses to load anything with Mission Equipment Storage unless I manually edit the file to add the size.

[neoancient]

Provide unit file(s) per reporting instructions.

[assaultdoor]

I have no idea which units cause "Error parsing null!" I get eight of those errors in the logs immediately after an error about the modular weapons quirk on the Taranis and immediately before an error about modular weapons on the Nagasawa, but no unit is named.

For the Mission Equipment Storage, it appears to be literally any unit with Mission Equipment Storage that does not have :SIZE: information, such as this one.

NewBattleArmor.txt