ERROR : Error calling MIMEConvertCDParts(766)

[Rubeast]

I'm trying to convert a large NSF file (1GB with 12k of documents).
The end result gives me following info:
"INFO : Exceptions: 494 ... Documents OK : 11885 Untreated : 0"

In the beginning I'm getting this error a lot:
ERROR : Error calling MIMEConvertCDParts(766)
ERROR : Can not convert message 12251 to MIME
ERROR : #### Subject :

Once these errors are through, I get a lot of this:
ERROR : Ignoring message 11603 of form 'Memo' without MIME body
ERROR : #### Subject :

Smaller NSF files worked without problem.
I'm using Lotus Notes 8.5 32bit.
I'm using nsf2x-1.3.6-x86.
I'm exporting to EML since PST doesn't work.