To overcome this problem you need to do a small change in the DRC rule file.First go to /RuleDecks/Assura/DRC, then open
"G-DF-MIXEDMODE_RFCMOS18-1.8V-3.3V-1P6M-MMC-Assura-drc-2.10-p1.rul" file -> go to the last line which is "load( "./DRC/G-DF-LOGIC18-1.8V-3.3V-1P6M-Assura-drc-memory.rul" )".
Instead of "./" you give the full path of the file. For example
"load( "/cad/umc_180/RuleDecks/Assura/DRC/G-DF-LOGIC18-1.8V-3.3V-1P6M-Assura-drc-memory.rul" )". Hope this will work.