I had have that problem and solved this ussing the original XML generated by the SOLMAN.
In my case I have a distributed instalation, but when I look into the stack.xml I have changed it manually changing the hostname from DBHOST to Principal app Server.
I make this due to I was running the SUM from the Principal APP Server and I believe that SUM verify the hostname where it run. But I was in a error. You can chet that into the log file located into :
/usr/sap/<SID>/SUM/sdt/log/SUM
File:
SCAN_INBOX_0X.LOG for example SCAN_INBOX_02.LOG
Jan 3, 2014 2:08:04 PM [Info ]: Scanning Inbox for stack definition files...
Jan 3, 2014 2:08:04 PM [Info ]: Parsing stack definition file /media/SP9-PID/stack.xml...
Jan 3, 2014 2:08:04 PM [Info ]: SAP-NOTE tag is missing in the stack definition file.
Jan 3, 2014 2:08:04 PM [Info ]: STACK-SHORT-NAME tag is missing. The CAPTION of the stack will be used as stack name.
Jan 3, 2014 2:08:04 PM [Info ]: PRODUCT-PPMS-NAME tag is missing. The CAPTION of the product will be used as product PPMS name.
Jan 3, 2014 2:08:04 PM [Warning]: Software component SAP EHP1 FOR SAP NETWEAVER 7.3 : PI Adapter Engine (Java EE) - 09 (10/2013) found in stack definition file /media/SP9-PID/stack.xml is applicable for system SID: PID and HOST: ccros-sap-ap1, but the current system is SID: PID and HOST: ccsfsapdb02. This software component will be skipped.
Jan 3, 2014 2:08:04 PM [Warning]: Software component SAP EHP1 FOR SAP NETWEAVER 7.3 : Application Server Java - 09 (10/2013) found in stack definition file /media/SP9-PID/stack.xml is applicable for system SID: PID and HOST: ccros-sap-ap1, but the current system is SID: PID and HOST: ccsfsapdb02. This software component will be skipped.
Jan 3, 2014 2:08:04 PM [Warning]: Software component SAP EHP1 FOR SAP NETWEAVER 7.3 : NW Product Description - 09 (10/2013) found in stack definition file /media/SP9-PID/stack.xml is applicable for system SID: PID and HOST: ccros-sap-ap1, but the current system is SID: PID and HOST: ccsfsapdb02. This software component will be skipped.
Jan 3, 2014 2:08:04 PM [Warning]: Software component SAP EHP1 FOR SAP NETWEAVER 7.3 : PI Adapter Engine (Java SE) - 09 (10/2013) found in stack definition file /media/SP9-PID/stack.xml is applicable for system SID: PID and HOST: ccros-sap-ap1, but the current system is SID: PID and HOST: ccsfsapdb02. This software component will be skipped.
Jan 3, 2014 2:08:04 PM [Warning]: Software component SAP EHP1 FOR SAP NETWEAVER 7.3 : AS Java Extensions - 09 (10/2013) found in stack definition file /media/SP9-PID/stack.xml is applicable for system SID: PID and HOST: ccros-sap-ap1, but the current system is SID: PID and HOST: ccsfsapdb02. This software component will be skipped.
Jan 3, 2014 2:08:04 PM [Warning]: Software component SAP EHP1 FOR SAP NETWEAVER 7.3 : Enterprise Services Repository - 09 (10/2013) found in stack definition file /media/SP9-PID/stack.xml is applicable for system SID: PID and HOST: ccros-sap-ap1, but the current system is SID: PID and HOST: ccsfsapdb02. This software component will be skipped.
Jan 3, 2014 2:08:04 PM [Warning]: Software feature SAP EHP1 FOR SAP NETWEAVER 7.3 : Application Server ABAP - 09 (10/2013) found in stack definition file /media/SP9-PID/stack.xml is not applicable for Java stack. This software feature will be skipped.
Jan 3, 2014 2:08:04 PM [Warning]: Software feature SAP EHP1 FOR SAP NETWEAVER 7.3 : Process Integration - 09 (10/2013) found in stack definition file /media/SP9-PID/stack.xml is not applicable for Java stack. This software feature will be skipped.
Jan 3, 2014 2:08:04 PM [Warning]: Software component SAP EHP1 FOR SAP NETWEAVER 7.3 : Process Integration - 09 (10/2013) found in stack definition file /media/SP9-PID/stack.xml is applicable for system SID: PID and HOST: ccros-sap-ap1, but the current system is SID: PID and HOST: ccsfsapdb02. This software component will be skipped.
Jan 3, 2014 2:08:04 PM [Warning]: Stack SAP EHP1 FOR SAP NETWEAVER 7.3 for product SAP EHP1 FOR SAP NETWEAVER 7.3 will be skipped as it contains no applicable software features.
Jan 3, 2014 2:08:04 PM [Info ]: Parsing of stack definition file /media/SP9-PID/stack.xml has finished.
Jan 3, 2014 2:08:04 PM [Error ]: Stack definition file /media/SP9-PID/stack.xml contains no applicable stacks.
Jan 3, 2014 2:08:04 PM [Error ]: Cannot construct a support package stack from file /media/SP9-PID/stack.xml.
Jan 3, 2014 2:08:04 PM [Error ]: The given /media/SP9-PID/stack.xml xml file cannot analyzed for the Support Packages Stacks.
Jan 3, 2014 2:08:04 PM [Info ]: Scanning Inbox for stack definition files has finished.
Jan 3, 2014 2:08:04 PM [Info ]: Found 0 applicable items.
Hope help,
Jose Maciel