Writing of vdf files with IDL extension not working with Vapor 2.2.4

Hi, with the new version 2.2.4, I can't write out vdf files anymore from IDL (was working for version 2.2.2). The problem occurs when calling "VDC_OPENVARWRITE", giving the following output: % VDC_OPENVARWRITE: WaveletBlock1D() : WaveletBlock1D() : coefficientsD() : % Execution halted at: WRITE_VAR_VDF 161 /home/vg/write_vdf.pro It seems that there is a problem occuring within the IDL module. Can you give my any advice how to further debug? A short excerpt from the IDL script is: ---- dfd = vdc_bufwritecreate(vdffile) dim = vdc_getdim(dfd, -1) vdc_openvarwrite, dfd, ts, name, -1 <----------- don't get beyond that point (line 161) for z = 0, dim[2]-1 do begin vdc_bufwriteslice, dfd, float(var[*,*,z]) endfor ---- All previous calls were successful, so dfd, ts and name have proper values. The metadata object was initialized with "mfd = vdf_create(dim, levels)", hence without any non-default coefficient settings. As said, this error did not occur for the module of version 2.2.2. Best regards, Volker