Startup.s: error: A3903U: Argument 'ARM7TDMI' not permitted for option 'cpu'.

While trying to code LPC2148, I'm getting this error. I'm using,

KeiluVisionv5.31

Rebuild started: Project: lkn
*** Using Compiler 'V5.06 update 6 (build 750)', folder: 'C:\Keil_v5\ARM\ARMCC\Bin'
Rebuild target 'Target 1'
Clean started - Project: 'lkn'
deleting intermediate output files for target 'Target 1'
assembling Startup.s...
Startup.s: Error: A9580E: ARM7 is not available with the current toolkit and license. Check that ARM_TOOL_VARIANT is set correctly.
Startup.s: Check that your license details are correct in the License Management dialog of MDK. Additional information is available at:
Startup.s: www.keil.com/.../license_management.htm
Startup.s: If you need further help, provide this complete error report to your supplier or license.support@arm.com.
Startup.s: - ARMLMD_LICENSE_FILE: unset
Startup.s: - LM_LICENSE_FILE: unset
Startup.s: - ARM_TOOL_VARIANT: unset
Startup.s: - ARM_PRODUCT_PATH: unset
Startup.s: - Product location: C:\Keil_v5\ARM\sw\mappings
Startup.s: - Toolchain location: C:\Keil_v5\ARM\ARMCC\Bin
Startup.s: - Selected tool variant: mdk_lite
Startup.s: Product: MDK-ARM Lite 5.31
Startup.s: Component: ARM Compiler 5.06 update 6 (build 750)
Startup.s: Tool: ArmAsm [4d35ec]
Startup.s: error: A3903U: Argument 'ARM7TDMI' not permitted for option 'cpu'.
".\Objects\lkn.axf" - 2 Error(s), 0 Warning(s).

*** Performing Cross-Module-Optimization:
*** Feedback file '.\Objects\lkn.fed' not found.
Target not created.
Build Time Elapsed: 00:00:01