Error deploying PAR file from Developer Studio (NW04)

Hello,

i've got a problem while trying to deploy a PAR file from NW Developer Studio.

The PAR Export function says

"Unable to connect to the Portal",

the portal itself gives the following response:

"ERROR: Upload failed - exception caught: com.sapportals.portal.prt.runtime.PortalRuntimeException: Invalid content type submitted - no multipart data"

Deploying the PAR file manually using the Administration Console (system administration tab) of the portal works fine, but why doesn't the PAR Export function of NWDS?

Thanks in advance for any help!

Regards,

Jörg