One reason the "0 Items/Paths Analyzed" message occurs is because the constraint system has duplicate constraints. This problem can be caused by duplicate constraints in the UCF/NCF/EDN files; see (Xilinx Answer 18928).
A second reason this message occursis related to the prioritization between constraints. If the paths are covered by a FROM:TO constraint and a PERIOD constraint, the FROM:TO constraint will analyze the path. This occurs because the FROM:TO constraint has a higher priority over PERIOD constraints. The same situation can occur between an OFFSET constraint and a FROM:TO constraint. The FROM:TO constraint also has a higher priority over the OFFSET constraints; see (Xilinx Answer 13920).
A third reason this message occurs is that the timing group associated with the timing constraint has been removed by NGDBuild or the Translate process. Check the Translate Report, or the BLD file, to determine which timing group or timing constraint was removed or ignored. Following are examples from the Translate Report:
"--ERROR:NgdHelpers:702 - The TNM "PAD_CLK" drives the CLKIN pin of CLKDLL "$I1". This TNM cannot be traced through the CLKDLL/DCM because it is not used in exactly one PERIOD specification. This TNM is used in the following user groups and/or specifications:
TS_PAD_CLK=PERIOD PAD_CLK 20000.000000 pS HIGH 50.000000%
TS_01=FROM PAD_CLK TO PADS 20000.000000 pS"
"--WARNING:XdmHelper:644 - No appropriate elements were found for the TNM group "%s". This group has been removed from the design. No appropriate elements were found for the TNM group "!%1!". This group has been removed from the design."
"--WARNING:XdmHelps:645 - No appropriate elements were found for group "%s". This group has been removed from the design. No appropriate elements were found for group "!%1!". This group has been removed from the design. See warning(s) above for details of the pattern(s) that could not be matched. Note that patterns will match only signals driven by the given type of element, not instance names. To create a group using an instance name pattern, use the INST keyword to attach a TNM."