Problem Exporting then Importing GDS from Virtuoso

Dear All

i have a problem, i have a complete layout made from Encounter, and i managed to transfer it successfully to Virtuoso using OA database, now i want to export the GDS file from Virtuoso and then reimport it again in virtuoso also so as to check that the export was a success. the problem is that when i export the design and i specify the technology as "cmrf8sf" and the library is "My_Design" the export is done with some warnings:

" INFO (162): You have not used the viaMap option. If the OpenAccess design has native oaVia instances, use the -viaMap option for preserving oaVia instances in a Stream Out - Stream In round trip. Using the -viaMap option improves performance and VM usage of applications using the Streamed-In design.  For details on the viaMap option, refer to the "Design Data Translator's Reference" guide for XStream."

and

"WARNING (206): Path length 200 at location (1345000,901800) on layer 5 is less than 1/2 of path width 560. The path would be written in Stream file as is. To resolve this, fix the reported path in the input design and run the translator again."

 i think that both warnings are of no effect on the export !! but when i reimport my GDS file again with the same data as the export, i find out that the valid layer are only Metal 1 and Via 2 !!!!!!!

anyone know anything about that problem !!!

by the way, i use the kit IBM 130nm DM kit and i installed it correctly in my working directory

thanks in advance